Why is the Class 69 not a subclass of the Class 56?

[071]

Thanks - that was very interesting.

Although they looked the same in the bodywork, the Warships from Swindon (42) and North British (43) were completely different inside, not just engines and transmissions but all the subsidiary items as well, because North British had been allowed to do their own thing. If you were cataloging spares you needed two completely different sets for the two types. Not only that, but North British designed and built a significant number of the auxiliary items themselves instead of going to established suppliers, only to go bankrupt at the end of construction. The bodywork was designed by Swindon, and the drawings sent up to Glasgow, but not the internal layout. It was rather a shame, the WR view was the best design NB did was the initial D600, then all the competent technical team saw the writing on the wall and left. There are drawings around of NB's own first pass at a Class 43 bodyshell, sort of a blend of the D600 and D6300, very sad looking at the front, which must have caused apoplexy at Swindon and an instruction to "send them ours".

== Doublepost prevention - post automatically merged: 15 Nov 2021 ==

How many more diesel locomotives are you expecting to be built in the next ten years?

Ok, you've got me there. Probably not many.
I suppose it was a desire for neatness and efficient use of numbering.

 

[Neptune]

Have we had these yet??

(Image shows a Network Rail Class 97, a renumbered Class 37).

Locos have been classified as class 97 for decades when they were allocated to the RTC. Some heavily modified, some not so.

 

[coppercapped]

How many more diesel locomotives are you expecting to be built in the next ten years?

It would not surprise me in the slightest if these are the last pure diesel freight locomotives to be built for this country's railways.

 

[Towers]

Locos have been classified as class 97 for decades when they were allocated to the RTC. Some heavily modified, some not so.

Ah.... Fair enough!

 

[sprinterguy]

Weren't the 97s modified for ERTMS testing on the Cambrian? I think one/some of them have since made it into preservation, as I'm sure it was one of these that ran away and belted a preserved mail carriage at one of the heritage lines.

All four of the 97s are, to the best of my knowledge, still available for use by Network Rail on the Cambrian line or elsewhere on the national network as required.

The loco involved in the runaway and collision on the Great Central Railway was 37198, which was purchased by and received the livery of Network Rail, but never saw use with them on the main line and was never renumbered as a class 97. After a period providing spare parts to the operational 97/3s at Derby after the collision, it has since been cosmetically restored and moved to the Head of Steam Museum at Darlington for preservation.

 

[Towers]

All four of the 97s are, to the best of my knowledge, still available for use by Network Rail on the Cambrian line or elsewhere on the national network as required.

The loco involved in the runaway and collision on the Great Central Railway was 37198, which was purchased by and received the livery of Network Rail, but never saw use with them on the main line and was never renumbered as a class 97. After a period providing spare parts to the operational 97/3s at Derby after the collision, it has since been cosmetically restored and moved to the Head of Steam Museum at Darlington for preservation.

Ah, that explains it then! Many thanks for that

 

[norbitonflyer]

Fairly minor engine differences have justified different TOPS classes in the past - see classes 24/25, 26/27, and 44/45, in each case the latter merely being an uprated version of the former. Other classes with different engines in otherwise similar locos include 08/10 and classes 42/43 (but not the Rolls-Royce engined class 17s)

Another anomaly. The BR-design Type 4s were classified 45 or 46 depending on whether they had Crompton Parkinson or Brush electrical equipment. The Type 2s also had two different makes of traction motors (BTH or AEI) but were all classified 25. (As noted above, there was an earlier version of each type with a lower-rated engine - class 44 and 24 respectively).

The difference between Class 08 and Class 09 would not normally have led to a different classification (there were Class 31s with different gearing and thus maximum speed), but they totalled 1024 locomotives which would have broken the TOPS numbering scheme, even after excluding the Crossley, Lister-Blackstone and Blackstone-engined locos which between them added another 169. They were all withdrawn in 1966-72, although the Blackstone version was allocated a TOPS class (10) .

In the event, forty Class 08s had been withdrawn by the time individual TOPS numbers had been allocated, so there would have been enough room for both surviving variants to be one class.

 

[43096]

If anyone is looking for some sort of consistency on what criteria give the need for a new class number versus a new sub-class, or even no renumbering at all - don't. There is no consistency and never really has been - it's consistently inconsistent. Take the different engines for Class 47s: 47601 and 47901 got new sub-classes, but Class 57 was a new class. And then the Class 43 power cars: some renumbered, some not.

 

[xotGD]

And then the Class 43 power cars: some renumbered, some not.

Ah, but the numbering of DMU vehicles follows different rules!

 

[norbitonflyer]

Ah, but the numbering of DMU vehicles follows different rules!

Indeed - even when they turn up in EMUs (see the class 210 cars now in 455s) or vice versa (the ex-EPB 77xxx driving trailers in the "tadpole" units. In both cases they kept their original numbers.

The only DMU vehicles I can recall getting new numbers were
- the non-driving motor coaches from the Trans Pennine Units (Class 124) - renumbered when converted to trailers
- motor coaches renumbered in the 79xxx series when one of their two engines was removed
- the mass renumbering of all coaches in the 50xxx and 56xxx ranges to avoid duplication with locomotives
- a handful of trailers also renumbered to make way for the Class 59s
- class 155 cars in the 57xxx range when converted to class 153 had 50 added to their numbers so that their last two digits corresponded with their new unit numbers

 

[JKF]

Plus, the GBRf 73/9s and the yellow 'Minion' 73/9s are different internally, so it is two different locos sharing the same subclass.

A precedent for this would be the 37/9s, though they were test beds really.

 

[Helvellyn]

The six Class 73/0s (JA) were nearly Class 72, which would have seen the 73/1s (JB) numbered 73001-73042.

The nineteen 33/1s with EPB multiple working equipment were nearly Class 34.

Given some of the Type 4 numbering it's surprising the first twenty 47s, 'Generators' 47401-47420 weren't a separate class given they essentially had Class 46 electrical equipment. This would have made the other 490+ Class 47s into Class 48s, and the five initially classified as Class 48 due to different engines (but re-engined before TOPS) into Class 49!

 

[norbitonflyer]

The six Class 73/0s (JA) were nearly Class 72, which would have seen the 73/1s (JB) numbered 73001-73042.

The nineteen 33/1s with EPB multiple working equipment were nearly Class 34.

Given some of the Type 4 numbering it's surprising the first twenty 47s, 'Generators' 47401-47420 weren't a separate class given they essentially had Class 46 electrical equipment. This would have made the other 490+ Class 47s into Class 48s, and the five initially classified as Class 48 due to different engines (but re-engined before TOPS) into Class 49!

The gaps in the TOPS numberings may be explained by such having been the original plan. Other possible "classes that never were":

18 and 19 - There were three subclasses of the Class 17 "Claytons" - 17/1 Paxman engine, GEC generator: 17/2 Rolls Royce/GEC,17/3 Paxman/Crompton Parkinson (the latter built by Beyer-Peacock)
32 - the Hastings- gauge variant of the Class 33
36- Perhaps LMS No 10001 was still extant when the TOPS numbers were being devised?
38 and 39 - I believe there was some variation between the 37s - from D6819 I think, hence the renumbering of D6700 as 37119 and D6819 to 37283 (D6983 having already been withdrawn)
51, 53 and 54 - Class 47s before they were de-rated? (53 was of course later used for the "Falcon" prototype)