TOPs numbering

[ChrisCooper]

I'm wondering if anyone knows how TOPs numbers are allocated to new locos and units. I know about the different types, but I mean who decides on the exact number? When it comes to DMUs and EMUs, the BR ones were mostly in order, 1st generation DMUs being 101 to 131, Pacers 140 to 144, Sprinters 150 to 159. EMUs run from 302 to 325 with only 316 and 324 missing (what happened to them?), with 301 missing as AM1s were withdrawn pre-tops. 370 was an oddity. SR units were all pretty well ordered, with the numbers actually being very based on the type of unit. I presume the 165 and 365 take their lead from the 465 (which refers to a 4 car inner suburban networker). Since privatisation though numbers have been all over the place. There seems to be a preferance for 0s or 5s (bit like a tombola), although some odd ones like 357 which although related to 375 seems almost random, as does 458. 444 I suppose was chosen due to being similar to 442, and 460 was already taken leaving 450 for the other Desiro. Post privatisation DMUs seemed to be very much sticking on the 0s and 5s, 170, 175, 180, 185, with varients counting up from them (currently just 171 and 172, but I presume any "Desiro Light" would be a 186).
I particularly wonder when numbers will be recycled. Loco numbers already have, as with the exception of AC electrics (where 94 on is available) there is not a lot of space, especially as quite a few types were allocated a TOPs number but never entered service. How long before we start seeing 1st generation DMU and Mk1 EMU numbers re-used?

 

[driver9000]

The Rolling Stock Library at Derby allocated numbers to new and existing rolling stock.

Outside of the numbering segreations (ie DMMUs 1xx DEMU 2xx etc) I'm not sure how they decide on the actual numbering, the class 70s were originally supposed to be 68 but was changed for some reason. A locomotive cannot share a number with a coach so there cannot be a locomotive numbered 57147 as this is occupied by the DMS of 150147.

 

[GB]

I must adimit I am not at all clued up on TOPS and how stuff is allocated but why exactly can't there be a 57147? (there is a 66147)

 

[CarterUSM]

I must adimit I am not at all clued up on TOPS and how stuff is allocated but why exactly can't there be a 57147? (there is a 66147)

Because 57147 already exists as a DMS of 150147, duplication isn't permitted.

 

[FLHH East Anglia]

I must adimit I am not at all clued up on TOPS and how stuff is allocated but why exactly can't there be a 57147? (there is a 66147)

answered above by driver 9000

 

[GB]

Doh, I get it now

 

[The Engineer]

I must admit I am not at all clued up on TOPS and how stuff is allocated but why exactly can't there be a 57147? (there is a 66147)

As Driver 9000 stated you can't have a loco number that is the same as a carriage number, and vice versa.

The people who CHOOSE locomotive or MU class numbers, and carriage numbers, tend to be the rolling stock owners - sometimes the operators. But they have to apply to the rolling stock library for authorisation, and they check there are no registered vehicles already in the number ranges requested. You'll note some try to tie carriage numbers to their unit numbers (BR didn't do that....)

 

[CarterUSM]

Am i right in saying that part duplication is also avoided , for example, there is a 156433, but not a 158433, obviously because the DMS's in both classes are numbered 52/57 but i am sure there are better examples than that!

 

[driver9000]

The people who CHOOSE locomotive or MU class numbers, and carriage numbers, tend to be the rolling stock owners - sometimes the operators. But they have to apply to the rolling stock library for authorisation, and they check there are no registered vehicles already in the number ranges requested. You'll note some try to tie carriage numbers to their unit numbers (BR didn't do that....)

BR did begin to tie vehicle and set numbers together with the Sprinter types being 57xxx and 52xxx which to me is a perfectly logical thing to if the number sequences are available. I'm not so clued up on the vehicles of 16x units etc but I imagine there is a similar vehicle numbering system in place for them.

 

[jopsuk]

did see today that Crossrail has reserved Class 345 for the rolling stock for the line- presumably the Rolling Stock Library is these days administered by Network Rail? Class 341 was the number that BR/NSE had reserved for a Crossrail Networker variant. Thameslink project has not reserved a number for the NXEMU stock for the line- again, NSE had proposed a Networker variant class 371.

 

[driver9000]

I think it's Atos Origin that run the RSL.

 

[Helvellyn]

Re-use of numbers has already begun.

The 170/171/172 DMUs use the 50xxx and 79xxx series, which were previously used by first generation DMUs (50xxx vehicles became 53xxx under BR in the mid-1980s to avoid a clash with the Class 50s).

The Class 350/2 and 379 EMUs are using numbers from the 61xxx series for some or all of their vehicles, which were used by BR for first generation EMU Driving Motor vehicles.

There has also been a move into the loco-hauled number series for the Class 378 and 380 vehicles, which are numbered in the 38xxx series that was reserved under BR for BSKs. If this trend continues then the 39xxx series could also be used by EMU vehicles. Other coach number series that could be used by EMU or DMU vehicles (and which have never been used) if this trend continues are 22xxx, 23xxx, 28xxx, 29xxx and 32xxx.

 

[Peter Mugridge]

I think there is a specific time limit after which the re-use of a number is permitted, but I cannot remember how many years it is, except that it's not a nice round number like 10 years.

 

[Helvellyn]

I think there is a specific time limit after which the re-use of a number is permitted, but I cannot remember how many years it is, except that it's not a nice round number like 10 years.

For some reason 7 comes to mind, but hopefully someone can confirm (or refute) me on that!

Not sure if it applied during BR days, when stock was renumbered: -

* Class 101 TSLs to clear the 5910x series for the ARC Class 59s
* Class 205 DMBSO 60100 for Class 60100
* Mark 1 BGs in the 920xx series (renumbered as 929xx) to clear that number range for the Class 92s

 

[Peter Mugridge]

7 years does ring a bell with me too.