My idea: Post-TOPS class codes

[squizzler]

The TOPS numbering scheme was a product of the technology of the day which would not be a factor with modern technology. If the opportunity arose to renumber all British rolling stock, what would be the best way to go about it?

A new numbering scheme should focus on multiple unit configurations, because that makes up almost all the UK railway scene. Locomotive and coach numbering schemes should fit in around this.

Ideally it should encode the most relevant information. The resulting codes may be longer than TOPS numbers but be easier to remember because they are informed by the characteristics of the unit. So for a first stab at things, I present the following:

• Number of vehicles in unit. Like the Southern numbering system commences with number of coaches (e.g. 4PEP, 4DES etc). Another scheme could express unit length in metres, which would make the scheme agnostic of coach length (articulated units are shorter) I have not done that. In locomotives, this digit would not be needed, unless multi-section locomotives made an appearance.
• Intended Usage. A locomotive might be either Heavy Haul or Multipurpose. Multiple units (or trailer formations) might be Regional, Intercity or Commuter.
  
• Power output. For locomotives this can be installed power. For multiple units this can designate the power to weight ratio (which will indicate both acceleration and top speed) (0 = unpowered trailers etc, 9 = embodiment of superpower). With locomotives the same power bands will include electric or diesel (under whichever energy source is greatest in case of bi-mode or tri-mode), so even a powerful diesel like the class 68 would be only middling at best, I used power 4 in the example.
• Power type. British rail used to use a letter prefix (e.g. D for diesel, E for Electric) prior to TOPS. There can be more designators now because of the number of different power combinations available. (N= unpowered, ED = electro-diesel bimode,
  
• EDIT: Serial number of loco / unit (not used in examples)

So for current trains, a Transpennine Mk5 set with class 68 would be 5I0N + M4D
A class 800 set (5 car) would be 5I7ED
Intercity 125 is a bit trickier (is it locos plus fixed formation trailer set or a multiple unit?) but I would treat it as the latter (7I5D for a seven trailer set) counting only the passenger cars for the prefix number so that passenger capacity of something beginning with the number 7 is the same as that for distributed traction. Anglian 755 Bimode with four passenger trailers and one power car would therefore be 4R7ED
A class 70 locomotive would be H4D
A pacer would be 2C3D

I have disregarded some obvious things like wheel arrangements (locomotives might be C for Co-Co, etc and passenger stock might distinguish bogies vs single wheel pairs as per Pacers and Talgo, regular bogies vs articulated). Other characteristics might be added or omitted on personal preference. What would your ideal numbering scheme look?

 

[gazthomas]

R2D2? C3PO?

I'm not sure of your approach but I think renumbering is long overdue

 

[squizzler]

Actually you have stumbled on something I did on purpose which was to alternate the numbers and letters. The power type might be a single letter or a combination (ED=electrodiesel, etc). Doing it this way means people should't mistake it as electric with the D signifying another quality, assuming they know letters and numbers alternate that is.. You might also get additional letters in the category for purpose of train, an intercity fixed formation might get additional letters if it's got a parcels carrying capability, restaurant cars or sleeper cars, etc.

Perhaps I achieved my aim of a memorable system if we can all remember the similarly concocted names of the Star Wars droids!

 

[squizzler]

Addition to the above, since we have separated strings of numbers and letters the locomotive power output can be expressed in Kw/100. This would express a class 68 with it's 2800Kw engine as class M28D. The very similar power class 70 (2750Kw, but we round to nearest 100Kw remember) would be H28D.

I digress of course, the multiple units are more important to get right! These would retain a single digit approximating to power-to-weight ratio as a surrogate of on-road performance.

All the above of course is just before the serial number of the locomotive or unit, so for our examples 70004 The Coal Industry Society is H28D004, 800306 Harold Day DSC / Allan Leonard Lewis VC would be 5I7ED306, etc

 

[cosmo]

If it ain't broke, don't fix it, IMO.

Besides, 142001 is a lot easier to roll off the tongue than "2C3D unit 2001" I mean there's some tweaks to the system one could make, but for the most part it works as is.

 

[pdeaves]

(0 = unpowered trailers etc, 9 = embodiment of superpower)

The trouble with this arrangement is, with ever more powerful motors/engines/etc., you will find that sooner or later everything ends up in 9. Household appliances are virtually all efficiency A now as everything improved and there is no way to tell them apart.

 

[xotGD]

Would a powerful freight locomotive be a Class 9F? Sounds somewhat familiar!

 

[cosmo]

If I were to re-organise the current system though, I'd do as follows:

Class 0xx - Loco classifications remain unchanged, as these are rarer than MUs anyway.
Class 1xx - commuter DMUs (up to 100mph) (Class 230 would move into this class, as Class 130)
Class 2xx - high-speed DMUs (over 100mph) (Class 180 would move into this class, as Class 280)
Class 3xx - 25Kv overhead EMUs (Class 350/1 does not move out of this class as most 350s do not have a 3rd rail shoe. Class 711, 720, 730, 745 and 755 move into this class, as classes 311, 324 (next closest to 320), 330, and 346 (next closest to 345))
Class 4xx - 750v 3rd rail EMUs (Class 701, 707 and 777 move into this class, as classes 401, 407 and 447)
Class 5xx - Bi-mode MUs (Class 700, 710, 717, 355 all move into this class, as classes 500, 510, 517 and 555)
Class 6xx - Tri-mode MUs (Class 769 moves into this class as Class 669)
Class 7xx - High speed MUs (Eurostar, HS1/2 etc.) (Class 373, 374 move into this class as classes 733, 734 as not to clash with actual unit numbers.)
Class 8xx - As above (high speed I feel is going to become a thing, quickly. IEPs do not change class.)
Class 9xx - Departmental/non-NR units (no changes needed in this class to my knowledge).

I've probably missed a clash or seven here so this list is subject to revision. If we really had to invent a new system though... just go 4 numbers instead of 3!

 

[squizzler]

You proposal has benefits over the ad-hoc class numbers we are currently stuck with, but again why would you limit yourself to just numbers if that was no longer technically a constraint? It would be much better to use letters as well. I subsequently thought that it would be better to denote subclass with letter rather than number, as the class 47 for instance almost ran out of subclass. That is perhaps also because the subclass "hijacks" the first digit of the serial number so when you hit 99 of any type you need to roll into the next subclass.

Also does anybody else think manufacturers codes within the class identifier might be a good idea, A for Alstom, B for Bombardier, C for CAF, etc?

 

[ac6000cw]

There are established UIC (International Union of Railways) numbering systems already for powered rolling stock - https://en.wikipedia.org/wiki/UIC_identification_marking_for_tractive_stock - passenger hauled stock - https://en.wikipedia.org/wiki/UIC_classification_of_railway_coaches - and wagons - https://en.wikipedia.org/wiki/UIC_classification_of_goods_wagons

To quote from the first Wikipedia page:

The method of applying and spacing the digits differs between operators. For example a British Rail Class 66 loco registered in Britain has been seen to carry the number: GB 9 2 70 0 066246-4, with the existing national number "66246" underlined, and lacking the operator identifying code.[6] Frequently the commonly used national part of the number is underlined in order to make it more readily identifiable.

 

[squizzler]

The UIC numbers are like ISBN numbers for books - it's the definitive reference - whereas the numbering system in your local library is equivalent to the national number. Two different things for different purposes.

The national nomenclature should ideally be a handful of letters and digits that encapsulates the key features of the class of stock. The TOPS numbers already do this after a fashion, but without the limitations of just a string of numbers imposed by the TOPS system (and doing away with the ad-hoc nature of it should be possible to come up with something more succinct.

The UIC system is still fundamentally about locomotives and hauled stock; a brand new nomenclature for national stock ought to be about multiple units first and foremost, and provide what is required to summarise the key attributes of the main types of unit. Instead it would be locomotives where compromises in the description might be allowed.