BR multiple unit numbering conventions

[Wilts Wanderer]

Go back to the 1960s-80s and there is a distinctive pattern in how certain EMU fleets were numbered to allow a set to be identified by its last 3 digits only (I.e. without the unit type.) It seems to have been done by Region, e.g.

ER Region
307 101-132
308 133-165
302 201-312
317 349-372
305 401-452
322 481-485
305 501-519
309 601-627
312 701-799
315 801-861

LM Region
304 001-045
310 046-095
312 201-204
317 301-348
321 401-448

Sc Region
303 001-091
311 092-110
314 201-216
318 250-270
320 301-322

Some fleets do not fit; 313 and 319 start from 001 upwards. 321s on the Anglia route were numbered 301-366 which overlapped with the 317 fleet. 323s on LM were numbered 201-243 which did fit by the mid 90s as the 4x Bletchley 312s were long gone.

You can see similar in the Sprinter families;

150 (prototypes) 001-002
150 101-150
150 201-285
155 301-335, 341-347
156 401-514
158 701-872, 901-910

159s do not fit but they ran on the Southern which had a completely different numbering scheme. The Turbo fleets sort of stand by themselves on WR:

165 001-039
165 101-137
166 201-221

None of the Pacer families seem to have followed a logical convention; all were delivered starting from 001 upwards although refurbishment led to 141 and 143 classes being re numbered into 1xx and 6xx set numbers respectively, and a number of Heaton 142s carried 5xx numbers during the gearbox replacement programme.

More modern fleets seem to have been delivered starting 001 or with numbering groups based within type only (e.g. 170!) or by ephemera such as original TOC, or seemingly no logical reason at all.

I can get why the original idea existed - pre TOPS it was a good idea to have unit numbers fully separated, and regions had autonomy. Likewise in the 1980s the Sprinter fleets seem to have been maintaining this tradition but I wonder why the 14x fleets did not, given they were being delivered around the same time/earlier?

Just interested if anyone has inside gen on the logic of numbering during the 80s - was there a rationale to it, or am I just seeing patterns where there are none really? The 158 fleet starting at 701 would seem to suggest there is, as late as 1989-91 - plus it also seems to leave a gap (6xx) for a non-existent 157 fleet!

 

[Magdalia]

ER Region
307 101-132
308 133-165
302 201-312
305 401-452
305 501-519
309 601-627

LM Region
304 001-045
310 046-095

Sc Region
303 001-091
311 092-110

When these were new, class numbers has not been invented. The class numbers were added later onto the front of the existing numbers.

You have missed out what became the class 306s, numbered 001-092, also some more class 308s, 313-321 and 453-455.

312 701-799

When these were new, the GN units were 312001-026 and the GE units were 312101-119. These later became 312701-726 and 312781-799.

312 201-204

When these were transferred to the ER, they were renumbered 312727-730.

315 801-861

These were originally allocated 315001-061 but I don't know if any actually carried those numbers.

 

[Snow1964]

Going further back, Southern Railway used blocks of numbers

2xxx for earlier electric units
3xxx for mainline electric units
4xxx for 4car suburban units

later BR used 5xxx and 7xxx series for suburban and mainline units

It also ran sets of coaches, but most of these were numbered with 3 digit set numbers. I think the lower numbers ones depended on the pre grouping origin of the stock (but would need to dig out old books to check)

 

[Pyewipecarshed]

Post TOPS it became convention to display the class number as well, so it didn't matter so much if the individual unit numbers were used more than once.
Sprinter classes 150-158 were given individual unit number series so that the vehicle numbers could reflect the unit number; e.g. 150201 comprises of vehicles 52201 and 57201. This in turn allowed staff to identify the toilet-equipped vehicle (52) and the luggage area equipped vehicle (57). I was taught this in conductor training with the slogan "5-2, do a poo!"
The only caveat to this is that 158's had a toilet in all cars, except on the 158/9, although the 57 car did have the lockable parcel compartment that nobody ever seemed to have a key for (!)
The 159's didn't fit series as they were originally built as class 158s and were modified and renumbered before entry to service, although I suppose they could have come in as 159873 onwards if so required...as the OP says, the Southern had to be different!

 

[Harpo]

Class numbers obviously caused some headscratching at first. When 302 302 came home from Wolverton to East Ham it wasn’t long before some yellow paint turned it back to plain 302.

 

[Peter Mugridge]

The 317s were originally 317 301 to 317 348

317 349 to 317 372 were the second batch.

Most got renumbered upon refurbishment.

 

[Magdalia]

The 317s were originally 317 301 to 317 348

317 349 to 317 372 were the second batch.

Most got renumbered upon refurbishment.

The GN units 317337-348 were never renumbered.

317501-515 were renumbered without getting a refurbish.

There was also a period when 317322-328 were standard class only and renumbered 317392-398.

 

[Peter Mugridge]

There was also a period when 317322-328 were standard class only and renumbered 317392-398.

That would be when they were running out of Fenchurch Street wouldn't it?

 

[PeterC]

When I commuted on class 306 units in the 70s I soon noticed that some had been reformed and bore different unit numbers at each end. How would these be identified?

 

[Wilts Wanderer]

Post TOPS it became convention to display the class number as well, so it didn't matter so much if the individual unit numbers were used more than once.
Sprinter classes 150-158 were given individual unit number series so that the vehicle numbers could reflect the unit number; e.g. 150201 comprises of vehicles 52201 and 57201. This in turn allowed staff to identify the toilet-equipped vehicle (52) and the luggage area equipped vehicle (57). I was taught this in conductor training with the slogan "5-2, do a poo!"
The only caveat to this is that 158's had a toilet in all cars, except on the 158/9, although the 57 car did have the lockable parcel compartment that nobody ever seemed to have a key for (!)
The 159's didn't fit series as they were originally built as class 158s and were modified and renumbered before entry to service, although I suppose they could have come in as 159873 onwards if so required...as the OP says, the Southern had to be different!

Aha thank you, so THATS the logic! Thats answered a question I’ve wondered about for years. The car numbers all being 52/57 would never have occurred to me.

Presumably then Pacers didn’t have this issue? I wouldn’t fancy having a poo on a bouncing 141 at 75mph but they did have toilets.

 

[The exile]

When I commuted on class 306 units in the 70s I soon noticed that some had been reformed and bore different unit numbers at each end. How would these be identified?

Presumably in the same way as classes 501-503, which never received unit numbers.

== Doublepost prevention - post automatically merged: 4 Oct 2025 ==

Aha thank you, so THATS the logic! Thats answered a question I’ve wondered about for years. The car numbers all being 52/57 would never have occurred to me.

Presumably then Pacers didn’t have this issue? I wouldn’t fancy having a poo on a bouncing 141 at 75mph but they did have toilets.

In the bad old days the 57xxx car also had the smoking section.

 

[Taunton]

In going back to the 60s-80s electric trains operated very much just on their own patch, and didn't need a national 6-digit number. The GE units didn't touch the WCML, and in turn were not connected to Glasgow, thus it didn't matter that there was an 001 on all three. Diesels less so.

An amusing moment that when TOPS renumbered all the diesel locos, each class restarted at 001, except for the small 03 shunters which kept the last 3 digits of their old numbers instead, with some big gaps in their list. Not that it matters but one wonders if some different clerk just did it a different way.

 

[frankmoh]

Does this mean there was 317317? I can see why they changed the numbering system after a bit.

Also I know the Southern Region is very different in terms of classification but I don't think there has been a more confusing TOPS number change than the 4TC units. Originally 442, the 491 and finally 438. The funny thing is that the 4REP trains that pulled the 4TCs were dismantled for their equipment, which would be used for the 'plastic' Class 442. Not confusing at all.

 

[Pyewipecarshed]

Aha thank you, so THATS the logic! Thats answered a question I’ve wondered about for years. The car numbers all being 52/57 would never have occurred to me.

Presumably then Pacers didn’t have this issue? I wouldn’t fancy having a poo on a bouncing 141 at 75mph but they did have toilets.

I'm not sure why the Pacers were numbered in a different series, but all vehicles were 55xxx. IIRC all driving cars had a lockable parcels section as built. The two car sets had a DMS (Driving Motor Standard) and a DMSL (DMS with Lavatory), plus the addition of an MS (Motor Standard) in the 3-car 144s. All vehicle numbers started 55 regardless.
They followed on within class, so for example the 142/0 had DMS 55542-55591 and DMSL 55592-55641.
The only concession to logic was in the DMS vehicles of class 144 which were 55801-55823 with the last two digits matching the unit number, e.g.144001 had DMS 55801. But then the DMSL's followed on (55824-55846) and so-almost- did the MS's, which were built later (55850-55859). I've no idea if there was supposed to be a 55847-55849, anyone know?
You could also work out a 142/1 unit number with maths from the side numbers; add 50 to the last two digits of the DMS and/or add 4 to the DMSL. So 142051 had DMS 55701 and DMSL 55747. Whether that was intentional or just coincidence I don't know.
Or you could just read the unit number, but where's the fun in that

 

[Magdalia]

That would be when they were running out of Fenchurch Street wouldn't it?

My recollection is Chingfords and Enfields, though they did make occasional appearances on the GN.

It was in the 1990s, 317322/323 became 317/7 Stansted units.

 

[Fleetwood Boy]

I’ve always been intrigued by the Gloucester class 100.

No other numbering series started x00 so far as I know? So why did Modernisation Plan dmus start at 100?

I’ve had two theories. One that it was simply that the clerk responsible adopted a different logic to all the others. Second that was it possible the Gloucesters weren’t initially planned to be retained so like the Derby and MetCam lightweight units they weren’t initially allocated to a class and then had to be tagged on at the beginning.

 

[Magdalia]

No other numbering series started x00 so far as I know?

We have class 700 running now.

 

[Sun Chariot]

We have class 700 running now.

And a "x00" for that GWR Hitachi thingy.

== Doublepost prevention - post automatically merged: 5 Oct 2025 ==

Presumably in the same way as classes 501-503, which never received unit numbers.

And the Manchester Bury class 504s. I wonder whether their DMS-DMBS pairs remained partners throughout, or whether any vehicle-partnering changed during maintenence / repair.

 

[jfollows]

I remember when I was young, I started going to school by train in 1970, I got my first Ian Allan Combined Volume and was initially confused by the EMUs that looked like mine with similar numbers, of course they were the AM5 units whereas “mine” were AM4. It took me a bit to work it out.

 

[Sun Chariot]

That would be when they were running out of Fenchurch Street wouldn't it?

I certainly saw 317 392 to 398 operating on the LT&S (I'd see them passing me while I waited on Shadwell DLR station). I can't recall if I photographed any of them in that guise. They had a green stripe in place of their former NSE red one.

I do have photos of the 310s on the LT&S; one shot of a 7-car set (the 4-car in NSE and the 3-car in Regional Railways).

 

[Fleetwood Boy]

We have class 700 running now.

Agreed, but these are recent numberings and the original TOPS logic has long been abandoned. Whereas class 100 was right back at the start and there were no classes 200, 300, 400 or 500 so far as I remember. Which is why it intrigued me.

 

[norbitonflyer]

Going further back, Southern Railway used blocks of numbers

2xxx for earlier electric units
3xxx for mainline electric units
4xxx for 4car suburban units

later BR used 5xxx and 7xxx series for suburban and mainline units

The SR also used 1xxx for the original 3SUBs (starting 1201), the trailer sets (1001, later extending down into the 900s when they reached 1199), the 4LAVs (19xx, later 29xx) and the original numbers of the various 2-car units 2NOL, 2SL, 2WIM (19xx, later 18xx), early 2BIL (originally 1890-1971, later 20xx) and 4LAV (originally 1921-53, later 29xx)

BR used 6xxx for the BR-design 2HAPs

== Doublepost prevention - post automatically merged: 5 Oct 2025 ==

Presumably in the same way as classes 501-503, which never received unit numbers.

I'm not sure how official it was, but the 501s were known by unit numbers corresponding to the car mumbers, which were all 611xx, 701xx, 751xx. (xx being the same for all three cars of a unit) Thus 5011xx etc.

== Doublepost prevention - post automatically merged: 5 Oct 2025 ==

An amusing moment that when TOPS renumbered all the diesel locos, each class restarted at 001, except for the small 03 shunters which kept the last 3 digits of their old numbers instead, with some big gaps in their list. Not that it matters but one wonders if some different clerk just did it a different way.

Most classes re-used the last two digits, except where several subclasses were being created. (An exception was Class 08, where it was necessary to close the gaps in a range ofm more than 1000). It just so happened that in most classes the second member of the class was still extant - the first of course being numbered Dxx00 and having to be renumbered in the first available gap

== Doublepost prevention - post automatically merged: 5 Oct 2025 ==

In going back to the 60s-80s electric trains operated very much just on their own patch, and didn't need a national 6-digit number. The GE units didn't touch the WCML, and in turn were not connected to Glasgow, thus it didn't matter that there was an 001 on all three.

There may have been some difficulty when AM3s were drafted in to Longsight depot to work the Glossop line after conversion to AC, as their nunbers duplicated those of AM4s

(Passengers on that line were used to sliding door DC 506s, so Longsight's resident slam door AM4s were not considered suitable)

== Doublepost prevention - post automatically merged: 5 Oct 2025 ==

I’ve always been intrigued by the Gloucester class 100.

No other numbering series started x00 so far as I know? So why did Modernisation Plan dmus start at 100?

Although there is some logic in how the 1st gen dmu classes were grouped, within those groups there seems to be little logic, certainly in classes 100-109. In order of numerical class size, they were

101 Met Camm (AEC engine) 2, 3 and 4 car (182 units)

108 BR (Derby lightweight) 2- 3 and 4 car (158 units)

105 Cravens (AEC) 2 and 3 car (125 units)

104 BRCW 2, 3 and 4 car (97 units)

102 Met camm (Leyland) 2 and 4 car (62 units)

100 Gloucester 2-car (40 units)

107 BR (Derby heavyweight) 3 car (26 units)

103 Park Royal 2 car (20 units)

106 Cravens (Leyland) 2 car (14 units)

109 Whickham 2 car (5 units)

(note - after the Met Camm and Cravens units were all fitted with new engines of one design, classes 102 and 106 were absorbed into classes 101 and 105 respectively)

In order of introduction:

106 8/56
101 10/56
105 2/57
104 4/57
100 5/57
102 6/57
109 8/57
103 11/57
108 7/58
107 12/60

In numerical order of class leader

101 50138
102 50250
100 50339
105 50373 (not counting 50249, which was a 1959 replacement for a written off class 101 vehicle)
106 50359
103 50395
109 50415
104 50428
108 50599
107 51985

 

[frankmoh]

I seem to recall something about it being "improper" to have a Southern Region train have a double zero at the start of its 4-digit number. For instance, the 4BEPs had the TOPS class of 410 but had numbers starting from 70xx instead of 00xxx. There was also the Class 480 8VAB (VEP reformation), and the 430 (one of the TOPS classifications for the 4REP).

 

[43096]

And the Manchester Bury class 504s. I wonder whether their DMS-DMBS pairs remained partners throughout, or whether any vehicle-partnering changed during maintenence / repair.

The 504s were DMBS-DTS.

 

[Mat17]

The 158 fleet starting at 701 would seem to suggest there is, as late as 1989-91 - plus it also seems to leave a gap (6xx) for a non-existent 157 fleet!

Possibly, or they were left vacant for heritage stock. The 101s took many of the 6xx series when refurbished.

 

[Helvellyn]

Possibly, or they were left vacant for heritage stock. The 101s took many of the 6xx series when refurbished.

It was for the Class 157, a proposed Hunslet DMU for Strathclyde PTE. However, before the 155 to 153 conversions were approved I think Provincal (as then was) looked at procuring a one-car version of the 156, so the gap might have originally been for that.

 

[Chrius56000]

Sorry for being a pain in the proverbial, has anyone got a summary list of coach/vehicle numbers of 1st Generation Modernisation Plan DMUs in numerical order of class type please? I don't think I've seen one on here before!

Chris Williams

 

[Sun Chariot]

The 504s were DMBS-DTS.

Oh my typo! Yes, I rode them a few times and my fat fingers typed the wrong thing.
OT but I've a few 35mm shots of them, freshly withdrawn en masse; 9 sets outside Bury old steam shed, snow on ground, a clear blue sky and winter sun. A fitting tribute.

 

[Pyewipecarshed]

And a "x00" for that GWR Hitachi thingy.

== Doublepost prevention - post automatically merged: 5 Oct 2025 ==


And the Manchester Bury class 504s. I wonder whether their DMS-DMBS pairs remained partners throughout, or whether any vehicle-partnering changed during maintenence / repair.

They appear to have been in fixed formations throughout.
Originally the DMBS's were M65436 to M65461 and DTS's M77157 to M77182, paired up in order i.e. 65436 with 77157.

When the fleet was reduced due to service cuts in the 1970s the cars withdrawn were 65436 to 65443 and 77157 to 77164. These were stored and later broken for spares and scrapped except for DTS 77164 which was rewired to AC and put into class 302 set number 244.

The remaining pairs stayed together; 77169 was withdrawn in the mid-80s leaving partner 65448 as a spare car until it too was withdrawn c.1987/8.
The remaining units became 504444 to 504447 and 504449 to 504461 on paper, with the unit number corresponding to the DMBS, i.e. 504444 had 65444, although the unit numbers were not displayed externally and the cars continued to show the vehicle number on the front end.
I don't know if the unit number was shown within the cab, but I sometimes bump into a driver who used to work at Bury, so I'll ask him if I see him!

Agreed, but these are recent numberings and the original TOPS logic has long been abandoned. Whereas class 100 was right back at the start and there were no classes 200, 300, 400 or 500 so far as I remember. Which is why it intrigued me.

According to Wikipedia (I know, I know!) class 300 was reserved for a proposed parcels conversion of some class 307s. It doesn't say when this was proposed.

 

[Peter Mugridge]

I'm not sure how official it was, but the 501s were known by unit numbers corresponding to the car numbers, which were all 611xx, 701xx, 751xx. (xx being the same for all three cars of a unit) Thus 5011xx etc.

It was official enough that most of those around at the end of their lives had those numbers applied to the front ends.

Here is 501 176 at Broad Street at 13.54 on 12th May 1985; the 501 is in very small type above the bigger 176 on the driver's side jumper cable cover; the 176 is also repeated in the secondman's windscreen using slot in numbers. All had the latter and most had the jumper cable cover numbers as well.