Numbering of classes 484 and 701

[cav1975]

I am an occasional user of SWR services and noted a class 701 train at Guildford on Saturday while waiting for my Portsmouth train. The vehicle numbers were 480022 etc with the fourth digit changing along the train, for example 484022. Are the first five units numbered differently to avoid a clash of vehicles 484001 to 484005 with Isle of Wight unit numbers 484001 to 484005 or do they clash?

 

[bb21]

They are the same. These clashes are no longer an issue, and have existed for quite a while now, eg. 385/0 have coaches numbered as 4440xx's.

 

[43096]

They are the same. These clashes are no longer an issue, and have existed for quite a while now, eg. 385/0 have coaches numbered as 4440xx's.

The clashes have never been an issue - indeed they are not clashes. A unit number is a completely different number range (or data field if you like) from an individual vehicle number.

 

[cav1975]

Thank yuo both for the explanations.

 

[norbitonflyer]

There are other examples
Class 745 TS in the 3320xx range
Class 385 DMS in the 4440xx range
Class 720 DMS in the 4501xx and 4505xx ranges
Class 717 DMS in the 4560xx range
Class 331 DMS in the 4660xx range

Classes 332 and 456 are now extinct, but the new car numbers were introduced when the older units were still running.

In the 1980s individual carriage numbers were amended on a fairly large scale to avoid clashes with locomotives and with rolling stock still carrying numbers in the Southern Railway series - although built post-nationalisation. This mainly affected DMU cars in the 50xxx and 56xxx ranges (renumbered to 53xxx and 54xxx), with a handful of 59xxx and 60xxx cars also renumbered. (Class 55 was already extinct).
Hauled stock renumberings were:
BFK 14xxx to 17xxx (as they duplicated SR-design 4EPBs)
CK 15xxx to 16xxx to 7xxx (ditto)
SK 25xxx and 26xxx to 18xxx and 19xxx
BG 81xxx to 84xxx
GUV 86xxx to 93xxx (if there are any GUVs still in use, they don't duplicate the new Class 93 locos)

For the same reason, there were no diesel classes 61 - 65, as these ranges were already in use for EMU cars.

 

[bb21]

The clashes have never been an issue - indeed they are not clashes. A unit number is a completely different number range (or data field if you like) from an individual vehicle number.

Not always, depending on the asset management/engineering software in use, but I think that may have been more of a consequential design due to the system avoiding clashes, rather than the cause (I'm sure someone will correct me if wrong). Since the move to six-digit carriage numbers this was no longer an issue as the two fields have been correctly separated across the industry (and probably for a good while previously already).

 

[CR165022]

This bit obviously isn't an official issue but when searching for allocations on websites such as https://www.charlwoodhouse.co.uk/ , units with carriage numbers repeated like that also show up on the allocation for the unit with that number.

For example, searching for 466003 also shows allocations for 331003.

 

[Glaswegian]

I think it is still true that clashes between locomotive numbers and carriage numbers are avoided. But a clash such as locomotive 03063 and carriage 3063 was tolerated.

 

[norbitonflyer]

I think it is still true that clashes between locomotive numbers and carriage numbers are avoided.

For example the proposed ETS fitted 99s will apparently be Class 99/4.
Also why 57s are 57/0, 57/3 and 57/6. (the 571xx, 572xx, 574xx and 575xx ranges being used by classes 150 and 156 - the 5730x cars were renumbered 5735x when converted from class 155 to 153, to match the unit numbers)

Somewhere there is a picture of a Deltic and a dmu "bubble car" with the same number at Haymarket, and I recall A4 Pacific 60009 had a photocall next to its diesel "number-sake" (although to TOPS the A4 would have been known as 98809)

== Doublepost prevention - post automatically merged: 19 May 2026 ==

But a clash such as locomotive 03063 and carriage 3063 was tolerated.

The renumbering of coaching stock happened in 1983.

Most 03s, and most mark 1 open firsts, had been withdrawn by the end of that year, but there were about sixteen duplicates where both were still extant at the end of 1983 - 03063 / 3063 being one of them.

The Class 09s duplicated the numbers of a small fleet of BSOs fitted with micobuffets in 1980/81 and renumbered in the 90xx range. There werer others in the 91xx range, but they had all been withdrawn before the Class 09/1s were converted from Class 08

The last 4SUBs, some of which had car numbers in the S8xxxS and S9xxxS ranges, were withdrawn in 1983