How British Locomotives are numbered

[johnchisem]

Following a comment on another post I realised that some people may not know how British locomotives are numbered. The following is meant as a guide and may contain small mistakes, feel free to correct or add details.

Steam locos were originally allocated names only. As the companies grew in size it became more convenient to use a number also. There does not seem to have been much logic to the actual numbers allocated. This did not cause too many problems until the 120+ small companies were grouped into the "Big Four" (LMS, GWR, SR, LNER) in 1923, this caused much duplication of numbers within a single companies' locos. Quite a lot of renumbering had to be done, but still with little logic.

One exception was the GWR which mainly used a 4 digit number in which the first 2 digits were the class, so a Hall loco was known as a 49xx. A King would be 60xx. The halls filled all the 49xx series up to 4999, but 5000 was a Castle class, so Halls went to the 59xx series. (Some oil burning Halls were numbered into 39xx)

When the Big Four were nationalised in 1948 even more duplication occurred so a major re-numbering occurred. GWR locos had cast number plates so they were left alone. SR locos had 30000 added, LMS 40000 (or 50000) and LNER had 60000 added. When the BR Standard locos were built tender locos were numbered 7xxxx and tank locos 80xxx and 9fs were 92xxx.

John

 

[johnchisem]

Original diesel/electric loco numbers

These were also fairly haphazard, very early diesels were numbered in the 1xxxx range, although later any number prefixed with a "D" was used. No logic again! D1 was given to Scafell Pike (a peak loco) and the Deltics went up to D9021. Electrics were given an "E" prefix. Multiple units were numbered with 5 digits with a prefix indicating which region they belonged to, later when the prefix was dropped some had to be renumbered to clear the way for locos with the same number.

John

 

[WileeCoyote]

Man and I thought the German system was rather confusing...:hehe:

WileeCoyote

 

[johnchisem]

Up to the present

In the early 1970s the TOPS computer scheme was introduced which brought about a major renumbering.

The first digit of the class number indicated what "type" the loco was, (type 1 were up to 1000bhp, type 2 1000-1475, type 3 1500-1750, type 4 2000-2750 and type 5 over 3000 bhp). So a class 47 (2750 bhp) was type 4, etc. The second digit just increased to separate different classes.

The third digit indicated sub-class.

So a 470xx number loco was an original steam heat loco
then a 473xx loco was a no heat loco
and a 474xx loco had electric heat.

bad example as 470s ran up to 47298!

later some were converted to push-pull locos becoming 477xxs.

Are you following all this? Mrs C thinks I've gone ga-ga.

I think it's time to finish for now, any questions are welcome.

John

 

[johnchisem]

Last bit for now!

Electric locomotives.

DC current locos were renumbered into the 7xxxx series. Mainly Southern Region third rail locos (71, 73, 74) and overhead class 76 and 77 (withdrawn before carrying new numbers)

AC locos were renumbered 8xxxx (eg 81,82 etc) And have now gone over into class 91 and 92, Likewise the class 66 and 67 diesels!

John

 

[johnchisem]

Mr Coyote, there IS some logic, it may be that my explanation is a little unclear, it was quite difficult to express. Perhaps questions and answers will help!

John

 

[AndrewH]

.........This did not cause too many problems until the 120+ small companies were grouped into the "Big Four" (LMS, GWR, SR, LNER) in 1923, this caused much duplication of numbers within a single companies' locos. Quite a lot of renumbering had to be done, but still with little logic.

One exception was the GWR which mainly used a 4 digit number in which the first 2 digits were the class

The pre 1923 GWR had the advantage at the Grouping of making up over 90% of the total locomotive stock of the companies that merged to form the enlarged GWR. Easy to change the numbers of the other 10%.

The SR, LMS and LNWR were conglomerations of at least three large pregrouping companies. They all renumbered in much the same way as BR did in 1948, they added a round number to the original companies numbers. For example the LMS left the Midland Railway numbers as they were, added 5000 to all London & North Western numbers and 10000 to the Lancashire & Yorkshire. This process meant that whatever logic had applied to the pregrouping companies was still maintained but made no sense in the new company.

The LMS reorganised its numbering continuously over its existence. However the LNER completely renumbered its stock in 1946 and at nationalisation had the most logical numbering series with locomotive numbers arranged by class and wheel arrangement.

BR actually only added 40000 to the LMS number. Most of the 50000 numbers carried by ex LMS stock had carried a number 10000 or higher prior to 1948.

 

[Harry_James_Potter]

In the early 1970s the TOPS computer scheme was introduced which brought about a major renumbering.

The first digit of the class number indicated what "type" the loco was, (type 1 were up to 1000bhp, type 2 1001-1499, type 3 1500-1999, type 4 2000-2999 and type 5 over 3000 bhp). So a class 47 (2750 bhp) was type 4, etc.

The exception to that numbering system was the Class 31s... They were never Type 3s to begin with and only when they did try to wind up the Mirrlees engines that high, they ran into bedplate fracturing problems.

They ripped them out and replaced them with good ol' EEs at 1470Horse. Still makes them a type 2.

And another exception is the experimental 47/9 with it's 3,000+ horse ruston paxman testbed engine.

regards

Harry

 

[WileeCoyote]

Mr Coyote, there IS some logic, it may be that my explanation is a little unclear, it was quite difficult to express. Perhaps questions and answers will help!

John

I can see the smallest hint of any logic in your posts, its just awfuly confusing, however in the subsequent posts, they are obviously the work of nutters:hehe:

WileeCoyote

 

[johnchisem]

And then we had PWM 650, DB968000, Lion and Falcon and DP3.!!!!!!!!! Even DELTIC..

It has been mentioned that my posts on this subject are a little confusing! I totally agree! However I stand by them and will leave them as they are, but welcome comments, views and above all questions.

John

 

[Paulsw2]

Having grown up with these numbering schemes, I feel quite comfortable with them, especially TOPS. However, I can imagine that trying to explain to the uninitiated, it rather sounds like the rules of cricket!

 

[AndrewH]

I can see the smallest hint of any logic in your posts, its just awfuly confusing, however in the subsequent posts, they are obviously the work of nutters:hehe:

Thank you for your professional assessment, we are all the better for your exalted opinion and infallible grammar.

 

[Henners]

observing locos and DMUs/EMus today, they are usually numbered with their class code first, then a set of 3 numbers

for example:

Class 66 Diesel Loco would be 66xxx
Class 158 DMU would be 158xxx

where there are subdivisions, e.g. with the class 150s (150/1, 150/2) the first 3 are the class code, then the 4th digit the sub-division

for example:

A class 150/1 would be 1501xx
a class 150/2 would be 1502xx


hope this has been usefull

 

[Stationbeem]

Even though this thread is over 3years old, I don't mind things like these being bumped as they contain a lot of information which may have been lost in the ether of time. Well done for the bump it gave me a further insight into the numbering system of each different class.

 

[BLACKWATCH]

Then there were the HST sets, where each power car carried its own 'class' No. plus the 'set' No.

Class 253 Set No. 253001 consisted of 2x class 43 locos plus Mk3 coaches

 

[teddytoot]

Let's add to the confusion! When the Southern Railway was formed in 1923, it did not renumber but added letters to the numbers; E (Eastleigh) for ex LSWR locos, A (Ashford) for ex SE and LCD locos and B (Brighton) for ex LBSCR locos. In 1931 this was replaced by a straight numbering system where 1000 was added to the "A" locos and 2000 to the "B" numbers and the "E" numbers stayed the same.

Then along came Oliver Bulleid! He invented a new system for his new locos based on the continental wheel classification system. Thus the Q1 class were numbered C1 onwards, the pacifics 21C1 onwards and the electric locos CC1 onwards. Presumably if they had been completed before nationalisation the diesel electric would have been 11CC1 and the Leader CC100 (?).

After nationalisation Bulleid's system was scrapped and the locos renumbered conventionally in the ex-Southern 30000 range.

 

[fran1]

I never knew there were oil burning Halls. I'll get my know all mate with that. You learn something every day and in my case forget tomorrow!!
How is the Jesson Way mob Mr Chisem?:hehe:

 

[Atlantis27]

Not forgetting that the LNER number system did something similar to the aforementioned Southern "prefix/suffix" system...

A prefix of "C" was ex-Great Central, "E" for ex-Great Eastern, etc...

Just something I picked up from a book I just read on Nottingham Victoria station.

 

[magickmaker]

Let's add some MORE confusion in.

With WW2, Numbering took another turn.

The Southern Railway picked up a number of USATC locomotives. These engines were given the odd S100 class designation. At least that was during the war. After it, the railroad which had bought 14 of the locomotives (well 15 one was for parts) rebranded them the "USA" class. No number.

 

[Atlantis27]

Oh, also, when LNER locos got renumbered to BR standard, a lot reverted to their pre-LNER numbers. That's why Flying Scotsman (GNR 103, LNER 4472) became 60103, not 64472...

This is fun :-D