More Tantalus Type Trius.....type 3 fantasy concoctions.

The BTC and BRB got it wholly wrong in ordering so many under-powered type 2 locomotives. You can tell me it is easy to say with hindsight, while at the time there were still many branch lines being operated by tank 'kettles' which required no more than type 2 or even just type 1 power to trundle along with their modestr services. However even at the time in the pilot programme it should have been clear from early experience that main line ambitions for the use of single locomotives really required type 3 and up over. They should have also been able to see the growth in the use of the lorry for light, rural mixed freight as a threat to the smaller tonnages that type 2 were invisaged to operate.

Perrcievere they did though, with huge orders being placed for the sulzer based units which became classes 24 through 27, and you can of course really include the EE type 1 class 20 in their ranks. The farce ran so high as to the re-engining of the brush type 2 "class 30" with a derated SVT engine which would have been between 1500 and 1550 hp standard traction rating for EE. Another arbitary de-rating incidentally was the v16 Maybach fitted in the Hymeks which actually had a standard and proven hydaulic traction rating of 1940 hp, but that was outside the actual type three desirable rating oddly enough. A poorly performing class 40 takes a while before it falls into being a type 3 apparently.

On the one end of events in a fantasy diesel scenario, english electric  would have offered a type 3 during the initial phase of dieselisation in the mid to late 1950s. Thus presenting a rival to the southern regions natty new sulzers, the later to become class 33s. This would have used in a 1956 scenario, the SVT variant of the engine in a body very similar to the eventual class 37, but with disk train indicator system. It would be light enough in design of course to be a CoCo, or potentially an AIA configuration. This loco would have undoubtedly proven its worth, as did the reliable EE engined class 31s, and BRB may have ordered a job lot of them, not being tempted away by the charge air cooled variant which was available from about 1958, essentially when D200 was delivered. However in fact we may then have been stuck with a smaller class of less impressive locos than the class 37, with the 37 maybe never happening until slab front ends came along, if at all.

Already by 1960 EE offered BR an uprated CVST class 40 (probably on CoCo with a medium body length) or the full 2000hp rating of the 12CSVT in the 37 format perhaps as a higher value, shorter maintenance interval loco for the types of express and semi fasts forties were allocated. In fact which ever way you look at it, 40s were a bit quicker on express services of upto 400 tonnes because they have higher gearing, more momentum, ra6 axle loadings and 250 more horse power while actually only hauling an additional quarter of a carriage difference in weight over a 'syphon'. Conversely their high gearing, greater inertia and slower pick up on the power unit via stepped control meant that they were a lot more pedestrian on stopping services where acceleration counts more than performance in the third field diversion.

An early first series dieselisation EE type 3 at 1500/1550 hp would have performed probably very similarly to a class 31 and rather like a sick class 37 ( eg 37108 and 37025 in 1982/84). An alternative to this option at the time of the baby deltic order, would have been a single 18 cylinder deltic lump rated at 1650 hp as it was in 'deltic' at the time, or a fully possible T12 version of the arrangement with turbo. While considering the same body and CoCo configuration of the EE type 3, you could fit a 24 cylinder deltic engine in there, and run as a type 4 with a rating of around 2200hp @1500rpm non turbo. In fact EE could have offered the Syphon G body and bogies as standard with a choice of power units as follows (by 1960):

1) Low maintainance 1500 hp SVT
2) 1500 hp T12
3) 1650 hp deltic 18
4) 1750 hp /1850* hp 12CSVT
5) 2000 hp high maintenance 12CSV
6) 2000hp 16 SVT forty compatible equipment , no boiler
7) 2200 hp T18 deltic
8) 2350 hp / 2700 hp 16 CSVT non bolier, but with ETH

* 1850 hp had been the standard rating for several export versions of the new CVST engine and 1750 was an arbitary down rating from 'full' marine rating of the CSVT in 1959 when the engines were ordered.

I have had a couple of folk state that the v16 would never have been fitted or could never have been fitted into a 'syphon G'. Firstly the size would most likely indeed proclude a boiler, but in fact of course the majority of 37s were delivered "NB" with the stonehouse boilers ordered for them mainly going into Brush type 4s at the time.
As anyone who has been through the engine room of a non boilered (never boilered) syphon will tell you, there is a large plinth of concrete which had to be installed to balance the locomotives in lieu of the boiler. Drivers referred to this as the 'band stand'. People further argue about the weight of a v16 espeically a CSVT version even without a boiler. However just a couple of years later, EE of course produced the Portugues class 1800 which are 108 tonnes, and in fact a 12CSVT was fitted in a 79 tonne meter gauge loco in the late 50s for export. The bogies' would probably need upgrading to class 50 / 55 standard but that is not a great difference in cost given the benefit of having a standard body over several power ratings and units. EE offered basically a stretched class 37 with the CSVT engine  @2350 hp, instead of further orders of the type 4 with 16 wheels. BRB in their folly declined this offer, stating that they wanted to continue with standard locomotives, which with hindsight seems rather short sighted when already the deltics had supplaced the D200s on the key ECML expresses and the ubiquitous 12LDA would push them almost into irrelevance had it not been for the D200s reliability and RA 6 rating. 2350 hp at under 120 tonnes all up weight with EE's higher voltage system favouring total acceleration speed, would have made for an impressive passenger and even heavy frieght (of the day )locomotive, pretty much well as capable as the rather lumbering 'peaks' with their massive tonnage. It has to be noted that Dp2 in fact produced significantly more horse power upto 25 miles an hour or so than a deltic which hauls on one engine up to approximately this speed, and when fitted with the KV10 load regulator, the light weight locomotive ( under 110 tonnes) prove exceedingly competent under taxing gradients and on express services.

Deltic power units would have been prohibitive for a mixed traffic class however due to their disliking for thermal cycling on start-stop services. Any of the above mentioned though would have been a hell of a lot of fun in a 37 body shell, with perhaps the most likely being a T18 being fitted into a sub class for operating lighter services on the WCML ahead of the advancing electrification in the 70s.

Sulzers  Wonderful 8 LDA engine should Get a Word in Edge Ways!!

Yet another rather tantalising option for type 3 fans in the initial period of short batch trials in the late 50s would have been an RA5 dual heat version of the southern region Sulzer type 3. This would have had to have three axeled bogies to accomodate the length and weight the boiler necessitated but it would have probably come in at around the same as the Brush type 2 and the 37. You could envisage this being a very useful bit of kit for depots already home to many 6LDA and 12 LDA locos who required some more grunt for semi fasts, light expresses and medium weight freights. Indeed so useful that an allocation to ScR would probably have negated the need for the reintroduction of the class 37 in the early eighties for the W. highland and Far North routes.

A little known fact I have  mentioned before is that the class 33 is in fact fitted with an engine with the same per cylinder rating as the class 24 and class 26 ie 1160 hp in their case, 1550 for the 33. This means that the loco could have been fitted with the intercooled 8LDA as a variant or from BREL as indeed the 25s and 27s were in effect. At 1700 hp in either a BoBo or on six axles, the loco would have been impressive, and in terms of the former of those two, it would probably have outrun just about anything on the rail network to 20 mph at least.

While on the topic of sulzer and their better power units (the 12LDA and 6 LDA suffering in build quality by them sub contracting out work and getting the whole 2750 hp rating build wrong on the 'duffs') the LVA units prove successful with in particular SNCF. They rated the 12 down to 2200 and even as low as 2000 hp, but there was also a v8 variant which picked up some type three ratings in its somewhat limited application. Given the 12 LVA was rated at 2650 and maybe a max 2750 in SNCF days, the 8 LVA would have come in at around 1800 hp if it was to be used in line with the much debated class '48' duffs which were not so duff. The LVA series was significantly lighter and more modern than the 1930s style twin bank 12 LDA lumps. The wee v8 is not bigger or heavier than in fact the 8 CSVT fitted to the portugeuse and the Irish bobo locos, so it could have been shoe horned into a class 33 shell, or of course just plonked into a class 31 body at least, or  a class 47 body shell to produce an RA 5 type 3 loco.
The 12 LVA sounded like a mad cross between a forty and an HST, whistling at idle and run up before shreiking as the revs came on. The 8 probably was much the same, just a third less so!

Just had a thought, suppose all the duffs were converted to 12 LVAs after the LDA   @2750 failure, and then say type two body shells are used with the v8, which would stll allow for room for the boiler?  The 8 LVA could then in theory be rated at upto 2000 hp being half a kestrel in practice. Presumably also a straight eight version could have been available with a rating above 1700hp. Essentially it is a very different engine, more so than say the RK 6 shunter EE unit is to the eventual 'slug' 6RKT.

While on air charge cooling, BRB could have thrown out their silly ideas of using the SVT further down rated and demanded that brush present a new loco to take the now proven 12 CSVT / probably a CoCo version of the 31. Ludicrous:? Well the class 47 very nearly had a cousin or contender which would have had the 16 CSVT engine in it as stipulated by BRB.

Beyond 1000 rpm......

The one higher speed engine tantalus I think many would like to have seen on BR, would be the diesel electric version of the Hymek. I rather think this may have been kept bobo but run without a boiler to keep weight down, but a CoCo would have been RA5. The germans ran at least one class as a variant to their populace v16 maybach single unit locos and they prove as reliable.

On to another new option is that by the mid 1960s Paxman were able to offer their v16 at over 2000 hp and their v12 was probably rateable at a type three level by then, soon to be included in the prototype HST at a higher again rating in the ventura v12 format. They had been run at this time in high thermal cycling environments being fitted to the ScR class 29, which achieved a reliability akin to other sulzer type 2s allegedly with these new power units replacing the NB built MAN designs. I rather like the idea that WR never had to get rid of their oil sloshers and that they ordered a fully british ventura v12 based type 3 AIA loco with dual brakes and an auxially diesel generator to take hydraulics into the 1980s and beyond. While ER would take a bobo type three to work end to end on sleeper services on the ECML and potentially on the freightliner container services during the daytime. A fully rated version then being used as a recovery loco for failed HSTs and other express trains on the ECML.

Finally while on the WR, it seemed odd that no one came up with a twin engined type 3 with two 800/900 hp units in it working two torque convertor transmissions, thus allowing for 1. redundancy / limping home or working light services on on PU. 2) piggy backing at gear changes as the westerns did, one bogie continuing in drive as the other declutches and changes gear.

Crazy, or the Brush of a Pen Stroke Away?

Of all these crazy notions what do I think the most likely to have ever seen the light of day been?

Top runners for production classes would actually have to be none of my favourites per se but>

short production runs and prototypes

1500hp early disk display syphon 12 SVT
1650 hp deltic syphon trial Deltic 18
2200 hp deltic syphon trial T18
1600-2000hp twin engined DH or DE on bobo

production

1500hp AIA class 31s / a silly 30 hp short

1700 hp Class '34' 8 LDA SR / WR ETH loco

1600/1800 hp v 12 Ventura single unit Bo Bo Diesel Hydraulic

1600 / 1800 hp ""    ""    ""    ""     "" 

Why these into production?  Well the first one is a no brainer, it was either an arbitary derating to conform to type 2 banding or Brush could have been asked to tweak 14 kw more out of their electric transmission without having bust a gut.

Also the second one seems to be the most likely of any sulzer option because 1( the 33s were successful early on 2) BR liked the straight LDA format a lot in its air charged cooled variant, they had hundreds and hundreds of the darn things and parts are largely standard to the 12 LDA. It could have ended up in an extention to the 33 order or in say a BREL AIA streched class 25. IMHO there should have been wide scale cancellation of all these vermin and upgrading to either the 8LDA or moving over to ruther orders for 12 CSVT.

I think also that an early to mid sixties vision of the folly of type 2 while the success of the paxman in the warship showed the way, an alternative to the v16 maybach may have arisen in a v12 1500 hp / 1800 hp ventura, thus allowing for the class 52 to be a true type 5 and 100mph operator by using twin venturas and thus making a standard set up for the higher horse power locos in these two brackets, with the Maybach and MAN warships scheduled for retirement or reeingining with the venturas over time.  A V12 ventura is probably also ligher than the Hymeks v16 so that they could be weighted down as an RA 5 loco.

DE ventura based versions may have come later either via the class 29 experience or by the HST programme and proposed tail/end freightliner high speed container services.

If you think any of this is really so very crazy, super deltic single unit syphon included at the fringe end, then think again about what the BTC / BRB actually did. It ordered the CoBos and the Baby Deltics. It allowed western region to have completely non standard locos to the rest of the system and little standardisation within those! It stipulated that locomotives which could have been built to 119 tonnes (class 40) and 128 tonnes (peaks) should be instead fitted with vastly heavy plate sided 1Co-Co1 bogies to 'spread the weight'. Superdeltics were on the drawing board. Deltic HST power cars were also penned with this  2200hp T18 in them.  A class 30 was uprated to 2000 hp experimentally with air charged cooling. EE built the C1800s for Portugal at 108 tonnes......

Why Was Truth Stranger than (my) Fiction?

The real problem was two fold. Firstly BTC/BRB rushed over the evaluation phase of the initial prototypes and first series of orders. Technology had also moved forward, basically all the first phase locos were about 1953 technology, while the big advances in air charge cooling came into effect in 1956-1958. Other major advances such as the KV10 load generator and more reliable high speed engines filtered through just a few years later in the early to mid sixties. The left had of the BTC knew fine well that the motorways and four axle truck were going to take light freight off the branch line connections, while the railway side seemed to bury their head in historic figures of light trains needing tiddly little 1000hp to 1250 hp to tinker around with them. They should have seen that the US style of multiple heading was wasteful for the UK system in light of this with type 2s being redundant in their youth,  and opted for more type 3s and 4s. They should have waited longer before ordering classes and stipulating power bands, in order to evaluate types and horse power ratings, while also considering the market for rail transport, in particular the type of frieght which would remain competitive and the emergence of containerisation.

In a sensible world, we would have had CoCo forties and peaks and a lot more syphon Gs and 'bean can' 33s. The uprated 2750 hp 12 LDA should have been rejected upon extended trials of a dozen or so units in favour of the 12 LVA or the 16 CSVT. We would have seen continuing work to uprate the deltic engine in the early 60s to allow for 3800 hp operation with ETH generation in the fleet and for the superdeltic to tackle the WCML and presumably follow the route to displace westerns on the WR. We should have seen uprating trials with the 2000hp v12 CSVT and the 2350 hp v16 for the orders of class 40s post 1960. A full prototyping should have been undergone for the D400 before they were ordered, and the class be standardised to the less out landish equipment with normal oil wetted air intake filters. And we should have seen a fleet of kestrels too on the v16 LVA running express trains in the forefront of expanding electrification and standard 120mph running on most major routes.

Business wise they should have indeed focused on two or three power unit types ( variants with common cylinder and piston units and other common items) from two or three manufacturers, and in terms of worrying about  competition in british industry, directed that primary contractors like BRCW and EE sub contract some components and building of structures to smaller firms like Bayer Peacock and the likes. They could have focused on a big three manufacturer route, those mentioned above, plius BREL when the offering or capacity could not be found. The BTC/ BRB could alternatively have stipulated supply of power units from two or three sources ( sulzer, EE/ruston-paxmans, Maybach Licencee in the UK) with different work shops assembling units, but really that is just not as desirable as a prime design house who create fuilly integrated machines. A counter agrument would be the Class30 to Class 31 upgrade, or the fact that the 6LDA locos could be built to very similar quality over many different workshops, or that EE used RSH for a very large proportion of their capacity outside the Vulcan productiuon.

Today we have not really any less of a crazy situation because rail operators and rolling stock owners invest so sporadically and in self interest that they loose much of the opportunity and will to standardise. New and rather ludicrous emissions standards exclude many from the market for power units which can fit into a loco while being clean enough. The future is uncertain, but without government legislation or a return to more public control and ownership it is unlikely that the nirvanna of standardisation will ever be reached.

The British Rail Class 38.......that never was

The class 38 was perhaps quite near to being a signed deal, but the new reduced cylinder type 4 or 5 freight loco was what actually transpired from the successful 37/9 trial.

But what would the class 38 have actually looked like? How would it perform? Would it be like the 60 - freight dedicated -or like it's type 3 cousins, a jack of all trades?

Historical Context

All of the type threes and the nearly type three class 31, had shown that their superior punch in a small package made them winners over the under powered type 2s. At this approximate power banding, 1.4kw, it was deemed potentially useful to continue with newer locomotives which would work medium freight services, track maintainance and perhaps passenger trains. Another main purpose of the 37/9 trial was to estabish if reduced number of cylinders could be effective in operation: ie the far higher power per cylinder offerings in fewer and in line cylinder arrangements would be as reliable as the somewhat over engineered V12 and V16s of the 1950s,60s and 70s which were to be replaced.

The obvious choice of test bed for the proposed class 38 was of course the class 37. The engine compartment and radiator surface-area could accomodate a wide range of power units (PU's) : all from the two straight sixes chosen, through the GM645 unit and even up to the v16s in valenta/ Vp 185 or perhaps an RK 270 v16 - remember the portugeuse C1800s where shorter and lighter than the cl. 50.

At the time though the principle cost concern was what diesel mechanics call "unit man hours", a unit being a single cylinder and thus a multiple of these being considered the key cost driver. Heavy maintainance on the RK16 was costly, and the newer RK 12 has often been quoted as "over powered" and relatively unreilable by drivers and enthusiasts.

The eventual move to fewer cylinder "units" prove not to be quite as smooth as the 37/9 trial, with the expensive mistakes made on the class 60 with the MB275T/ 8 PU. However, no matter the teething issues with the PU in the "tugs", man hours and replacement components are indeed the major cost in maintaining a PU. Thus both straight 6 PUs chosen fulfill this criteria and establish if higher pressure PUs could operate at least as reliably as the best examples of the class 37s at Cardiff Canton where the trial was initiated.

What Form for the Class 38 ?

The class 38 would of course have been a standard "slab end" loco and would have followed the conventions at the time in being either similar or even standard in some elemetns to the two other UK locos viz. 56/58 or the US built class 59 perhaps. Given the contract had been placed with Brush Traction Ltd, as per the class 60, then the appearance would have been no doubt standard to the front end of the 60s. In essence the class 60 body is just a reworking of the 47 and 56 stressed frame.

One variation could have been employing a "Bone" format akin to class 20 and 58: at the time of the 60 order, the bone format had been clearly shunned on BR with a preference for walk through bodies allowing all weather access for inspection. With the whole design strategy being based on in line PUs, then a good deal of inspection and repair could be achieved in situ within a full width body. Furthermore, this would allow for more space for inclusion of a (redesigned!) silencer unit.


To Co or not To CoCo....

The MB275 unit is despite being only 5 mm wider in cylinder bore, considerably heavier than the RK270-6Tt unit, and in fact heavier than the original 18 tonne 12CSVT fitted in the Class 37. Being two stroke, the engine has longer stroke than the RK 270 (mm) and in general is far sturdier built to accomodate higher compression. In addition the crank case is a larger volume with large inspection ports for each "big end/con rod" connection to the crank shaft.

Therefore if the MB275 had been chosen then the loco would almost certainly have been a CoCo.

Power Unit Deciding Ultimate Bogie Arrangement

BRB had been somewhat dissatisfied with the RK reliability and service costs and also the delivered performance in classes 56 and 58. The PUs required more servicing than desirable, and it was seen that less cylinder units could offer cheaper servicing. Dissatisfaction was also all too evident at some customers like Foster Yeoman who ordered the GM 645 based class 59s as a result of poor class 56 performance, the road to GM EMD being paved and the UK industry's fate being more or less sealed as 'also ran'. I actually saw a FS stone test train with double class 56s in 1985 at Bristol Temple Meads Station, a service which a single 59 could tackle. So the Ruston RK 6 (or eventually 8) engine was not perhaps the lead runner.

In the final reckoning of course,m the superior power rating of the the MB 275 stratight 8 over the RK 8 lead to the former being chosen for the type 5 project, the class 60. The RK 8 in traction set up would be at a maximum rating of about 2800hp in the late 1980s, probably being favoured at a lower 2500hp to extend service interval. Coupled to SEPEX or GEC-Alsthoms latest power delivery & wheel slip control at the time, then a 2500 rating would have outperformed all the 12LDA locos and probably the standard class 56s and 58s.

On the other hand, in defence of the Rustons offering, there were several classes existing at the time which had a longevity expected with their RK / C/ SVT power units: 08, 20, 31, 37, 50, 56 and 58. Many components were "backwards compatible" eg new pistons from 58s into 37s, engine blocks from withdrawn 56s in class 50 life extension and so on. The MB 275 was completely unproven in a traction environment at that time, and Mirrlees had not enjoyed a very enviable reputation for their other traction power units, being swapped out of at least two types of brush locomtives and not favoured in the HST/ IC125 contract despite being trialled.

The RK 6 is four stroke and therefore uses less lubrication oil and probably has a longer heavy-refurbishment programme than the 6 cyl, MB275. Class 37s had proven to be masters of the type 3 power range, over-shadowing performance of their heavy and sluggish big sisters the 40s and providing more reliable service than all other type 4s. So this also stood in favour of Ruston's offering.

Details of the 37/9 trial are not fully released to the public, but however several commentators at the time stated better delivery with the MB but better service interval on the RK. The RK unit was fitted with some complex turbo lag synchronisation control, delivering fuel slowly until the turbo pressure was achieved. Hence the name "slugs".

With the smaller and much lighter RK6 being chosen form of the locomotive, the class 38 layout could then be left a little bit more open: Co Co configuration with the compact RK270 6T would have necessitated ballasting for heavy freight allocation, or indeed in any intended guise over six axels, as it weighs several tonnes less than the 12 CSVT, being essentially a single bank of that v12 engine and more like a class 08 RK footprint! This ballasting could have been a usefulk feature, with variable axel loading facilitated by lifting out the ballast depending on route and train type allocations.

An alternative just for the sake of arguement, could have been an AIA configurations: this could free up the trailing axel for advanced hydraulic braking or a dedicated rheostatic brake "motor". There are some electrical advantages in having only four traction motors to feed at this ampage/ voltage range in traction power application: these are much speculated upon by class 31 enthusiasts in comparison to the more powerful 37s. Also given the advanced SEPEX traction motors being a likely part of the order, then this electro-mechanical advantage could have rendered CoCo uneconomic: ie utilising a maximum kilo newton starting and continuous effort for the total power out put and axel loading over two SEPEX thus negating using standard TMs or bothering to employ six such advanced TMs.

The obvious option for reduced cost though would have been to produce a BoBo locomotive: Less materials in a shorter locomotive. The RK 6 engine is only slightly larger and heavier than the 280mm bore 6LDA 28 engines engines fitted to so many type 2s on BR and further a field. Although I find no interwebie quote for the type 3 rated 8LDA unit from the class 33, It is probably slightly heavier than the RK 6.


The success of the class 33 could have pointed to a SEPEX based locomotive being a sensible BoBo "Little sister" to the class 60 project. In fact the entire class 38 project had already been achieved by Brush traction when they re-engined their own "mini grids" : a class of BoBo locomotives made for Rhodesia / Zimbabwe. These were fitted latterly with RK 8 cylinder engines with a rating IIRC of around 1800 to 2000 hp and a tonnage under 80 gross. These suprising cousins to the 56s did have some good web listings and images a few years ago, an excellent british export locomotive site being amongst them. However, due no doubt to both copyright issues on images used and sources, and the closed nature of Zimbabwe as far as the internet goes, details of these locos are beyond my patience to find. I would be grateful for any links to provide some providence in this case. I would be very grateful for any links placed in "comments" below, by means of providing providence for this class of loco!

Total wieght at under 78 tonnes would later be advantagous for track access charging. However, there are several stumbling blocks for this BoBo arrangement: firstly the type of duties expected of a type 3 would include the torturous routes negotiated by 37s:


One reason 37s were introduced to the WHL and FNL/Kyle routes was to both accelerate trains while reducing corner wear over the type 2 bobos. By 1986 though, articulated CP5 bogies had been deemed a success though so a BoBo could have been practical in a new build. So this is one factor to consider: route availability and effective wear and tear.

The RK 270 is a longer unit than the 6lda, thus taking up much of the space in a locomotive as in the class 33. This would mean that features like rheostatic heat dissapators or indeed an auxilliary ETH generator would be excluded. One final factor I come upon to negate the use of Bobo is that a modern CoCo is in effect an AAA configurations: each traction motor can be independently removed or supplied less power ( in fact any 37 TM could be bumped out of connection, so they were in fact not a series connected CoCo) Heat dissapation is also a major consideration in a 1.4kw plus PU system and 37s had proven that their high ampage and resulting power delivery at low speeds was ideal for the CoCo configuration. So given the demands of heavy frieght and gradient work as a replacment to the 37s and 40s etc, and supplement to type 4s and 5s, the 38s would have done well to benefit from wheel slip / traction control in CoCo set up.

Final comment on CoCo: if the loco was to be a true mixed traffic entitity then the fitting of a 400- 600 hp auxiallary would have rendered a 2000hp prime mover with SEPEX TMS in a modern loco more effective than any of the then current sulzer type 4s when hauling ETH stock. A CoCo would allow for both this and space to carry ballast, while most likely offering better wheel slip and power delivery management than a bobo at the time of potential ordering in the late 80s.

Conclusion on Format:

At the end of the day, given the class 38 order went ahead in the same time
frame as the actual class 60 order, , then the Mb engine would be the choice to offer standardisation between the type 5 and type 3 erm, 3.5. Hence the loco would really need to be a CoCo to carry the weight and no doubt tackle the thumping torque -amps delivery of the big two stroke PU. It may have even been desirable to use the exact same body shell to give even more standardisation.

Had the order been put out to tender a little later in hypothetical time, then one tendering partner would have been the GEC altsthom with their Prima format, which has by in large been manufactured in BoBo format in both electric locos and the GM 645 based builds including the class 67s. With the light RK in their portfolio, then the loco would almost certainly have been a bobo and perhaps run alongside the royal mail /BRB build of the rather horrid class 67s.

Had BR decided to be rid of the underpowered type 2 fleet at an earlier date when their obselecense was clear, say 1976, then they could have looked to rationalise over to 8lda and ETH for a great number of class 25s and then build a new BoBo with brush at the time of the 56 order, as per the Rhodesian mini-grids discussed above.

Workings for the Proposed Class 38

What would they have worked? Well of course they would have worked all those mid wieght, mid speed services and track maintainance duties which class 37s have only now been by-in-large withdrawn from. Thus the class 38 would have lead to an earlier demise of the majority of the class 37 and probably all other type 2 and 3s, if they lived up to their promise of longer service hours, lower MPC and faster HGR turn around.

The 38s would have offered the opportunity to replace the earlier sulzer 45/46s from freight duties and supplement 47 freights, perhaps offering a heavier over all standing lift. In pairs they would have outperformed all the single type 4s and 5s of the early 1980s ( a pair of 37s would out perform 56s and 58 in sinlge unit operations according to motherwell depot). In the rush to dieselise in a post war britain still having materials rationing, pairing locomotives was seen as wasteful. However it is common practice in most long haul countries, where by larger "robot" multiples are often only engaged for gradients or actually switched off when running the wagons on "light" return journeys. Given that a pair of 38s would put out "type 6" power with 12 cylinders and be able to run light journeys on one unit, there may well have been an ongoing appeal from managers at depots like motherwell, Eastfield, Immingham, gateshead and Cardiff Canton.

Passenger wise, the 38s would have seen some employment even if they were nominally a freight ony locomotive given the same developments in the private era as transpired. However any potential order would probably have kept an eye on WHL sleeper services, routes like bangor, scarborough, Hull, Aberystwyth, Welsh Border Route and the potential for electric units / forwarding services to be operated by a light and fuel efficient loco.

If the class had been ordered as a freight only, this would have been under the BR sector scheme and so there would have been some debate upon privitisation and the ubiquity of class 66s as to the class 38's utilitity.

Now we see that the class 15x series multiple units are seeing the end of their effective lives and indeed the later generation units are showing signs of deminishing reliability, the 38s could have picked up where the 37s left off, working long distance semi expresses and hauling both de-engined 156s etc and things like 318s on services to say Lincoln, Hull, Bangor, Abersysthwyhth and in Scotland.


Fleet Size and Order-Number ?

Given BRB were serious in replacing earlier loco types 2 and -3, then the order could have been in the region of 150 to 200 examples. The author considers that both a super low geared and a higher geared "stroke 4" passenger dedicated variant sub class could have been subsequent orders upon successful experiences in core frieghts.

However the type of sub 1000 tonne traffic was drying up and becoming uneconomic. Also passenger traffic was strategically set over to multiple units: there was hope on a larger degree of standardisation, economic viability and reliability, all of which have proven dubious and probably not of any benefit if you compared the second or third generation DMUs with running class 31,33 and 37 (with 35 in there for historical noeworthyness!)

In the privatisation period, then private owners would have been very happy to exclude everything from class 20 to class 37 and rather own a single type 3 for lighter workings where a class 66 burns a lot of diesel! However, they were otherwise delivered fleets of pretty reliable "legacy" locos at bargain basement prices: some speculate that the acquisition of locos was less than scrap value in the total equation. There was no impetus for a new type 3 post privatisation due to this and now with network rail being national they struggle on with legacy 37s etc while 66s and 60s are often seen on rather puny track maintainance or even weed killer trains, and class 67s have appeared on many services which were otherwise completely adequately delivered by class 37/4s. In 2008, a large number of class 60s were stored as were many 67s and even 92s. It was claimed that there was not the demand for these locomotives.

As of time or writing, with no credible incentive to reduce axel weights or introduce locomotives on semi-fast services poorly served by DMUs, then there is little sign of any possible replacement to the recently pensioned type 3s.


Conclusions

The worrying issue for us at the time of the 37/9 trial, was if class 37s would routinely become "slugs". However, the refurbishment and "reallocation" programme showed the 12 CSVT to be a venerable and over engineered item which would last at least another ten years as planned, and of course nearly three decades in profit making service in reality.

If the RK 6 was chosen, then the loco would have almost certainly taken a BoBo format, while the MB275 lump would necessitate six axels. Intriguingly, the RK 8 could also be fitted into an RA6 / 7 Bo Bo loco as brush had done some years earlier to their Zimbabwe-Rhodesian "mini grid" bobos. My speculation ends there.

From all accounts however, the straight sixes were always planned to go in a new loco or be a test bed for reduced "unit" cylinder practicality for the larger "8s", and the latter was the project goal which prove desirable and came to fruition.