BR Standard Classes - numbering gaps

[alexl92]

As I understand it, the BR Standard Classes were numbered as follows:

70000 Standard Class 7
71000 Standard Class 8
72000 Standard Class 6
73000 Standard Class 5
74000
75000 Standard Class 4 4-6-0
76000 Standard Class 4 2-6-0
77000 Standard Class 3 2-6-0
78000 Standard Class 2 2-6-0
79000
80000 Standard Class 4 2-6-4T
81000
82000 Standard Class 3 2-6-2T
83000
84000 Standard Class 2 2-6-2T
92000 Standard Class 9 2-10-0

Does anyone know why the 74, 79, 81 and 83000 series were left unallocated? I can't find a pattern in the numbering (other than 7XXXX for tender and 8XXXX for tank locos) that suggests they were leaving room for something specific - or did they genuinely envisage building more than 1000 of a particular class?

Also was there any particular logic in terms of which class numbers were assigned to which class or is it just random - any reason for example why 73000 was given to the class 5s?

Cheers

 

[dubscottie]

There were proposals for a class 5 4-6-2, a class 8 2-8-0, a class 6 4-6-0 and a 2-6-2 so that might explain the gaps.

 

[AndyW33]

Both the LMS and the LNER had undertaken renumbering exercises on various scales by the end of their existence because in the 1923 numbering schemes nobody had fully considered the possibility of very large numbers of loco in a similar class, and the advantage of keeping all the locos in a class with consecutive numbers.

Both railways had left gaps in their 1923 schemes for new construction, but when Stanier Black 5s ended up with 842 constructed, they ended up having to backfill numbers below the class pioneer, so the newest loco was the one with the lowest number rather than the highest.

Having actually built 842 locos of the same class, it would certainly be possible to envisage building more than a thousand of another. The team who would have devised the numbering scheme for the standards would have been around to see the failings of the 1923 scheme and left plenty of room!

 

[alexl92]

There were proposals for a class 5 4-6-2, a class 8 2-8-0, a class 6 4-6-0 and a 2-6-2 so that might explain the gaps.

A Class 6 2-6-2 or just another 2-6-2 of another power class?
A new standard 8F makes sense considering the WDs were built for low cost rather than longevity... What was the thinking behing the Class 6 4-6-0 if they had a pacific of the same - to satisfy the Western men?
And what would the advantage of a Pacific Class 5 be? Lower axle loading?

Both the LMS and the LNER had undertaken renumbering exercises on various scales by the end of their existence because in the 1923 numbering schemes nobody had fully considered the possibility of very large numbers of loco in a similar class, and the advantage of keeping all the locos in a class with consecutive numbers.

Both railways had left gaps in their 1923 schemes for new construction, but when Stanier Black 5s ended up with 842 constructed, they ended up having to backfill numbers below the class pioneer, so the newest loco was the one with the lowest number rather than the highest.

Having actually built 842 locos of the same class, it would certainly be possible to envisage building more than a thousand of another. The team who would have devised the numbering scheme for the standards would have been around to see the failings of the 1923 scheme and left plenty of room!

Fair enough - makes great sense!

 

[dubscottie]

A Class 6 2-6-2 or just another 2-6-2 of another power class?
A new standard 8F makes sense considering the WDs were built for low cost rather than longevity... What was the thinking behing the Class 6 4-6-0 if they had a pacific of the same - to satisfy the Western men?
And what would the advantage of a Pacific Class 5 be? Lower axle loading?

From the book I have (British Railway Engineering 1948-1980) it does not say what power the 2-6-2 would have been.

The 2-8-0 was scrapped due to the huge numbers of WD & LMS 8Fs built during the war.

Apparently the class 5 pacific but was dropped when the extra costs maintaining the trailing truck and the fact it would be too heavy (11 tons more than a 4-6-0) were taken into account. Basically it was a Standard 5 with bigger driving wheels.

The class 6 4-6-0 was to replace the Royal Scots, Jubilees on the LMR and the West Country class on the SR.

The list of locos to be replaced is interesting as it lists the LNER B1s as to be replaced!

The same duties could be performed by the class 5 4-6-0

 

[alexl92]

Fascinating, thank you! Maybe the 2-6-2 could have been a V2-inspired beast? Who knows!

 

[dubscottie]

Fascinating, thank you! Maybe the 2-6-2 could have been a V2-inspired beast? Who knows!

I am sure I have more.. Found damp mould on that book so need to go through the lot!

You might have saved my books!

 

[DPWH]

Remember that the Austerity type 2-8-0s and 2-10-0s were considered to be the first nationwide standards and numbered in the BR scheme:

Class 8F 2-8-0s Nos 90000-732
Class 8F 2-10-0s Nos 90750-90774
--- old post above --- --- new post below ---

Both the LMS and the LNER had undertaken renumbering exercises on various scales by the end of their existence because in the 1923 numbering schemes nobody had fully considered the possibility of very large numbers of loco in a similar class, and the advantage of keeping all the locos in a class with consecutive numbers.

Both railways had left gaps in their 1923 schemes for new construction, but when Stanier Black 5s ended up with 842 constructed, they ended up having to backfill numbers below the class pioneer, so the newest loco was the one with the lowest number rather than the highest.

Having actually built 842 locos of the same class, it would certainly be possible to envisage building more than a thousand of another. The team who would have devised the numbering scheme for the standards would have been around to see the failings of the 1923 scheme and left plenty of room!

Not precisely true.

The LNER renumbered all most of their stock in 1946.

The LMS never really did any mass renumbering. The 1905 Midland scheme basically held together for sixty years. The 1905 Midland on nationalisation was essentially repeated across four blocks, 5000-9999 for ex-LNWR, 10000-14999 for L&YR and 15000-19999 for ex-Scottish engines.

New builds were fitted in these existing blocks. There was some logic to this as the first new engines were basically to Midland design, the Horwich moguls being initially numbered in the L&YR series, logically. There was some renumbering in the early 1930s, to try to keep LMS standard classes with lower numbers, but this only affected a few classes. When Stanier came in it was mostly LNWR engines that were being withdrawn and replaced, so that's where the gaps were.

When new engines were built and were due to duplicate numbers, the new engines took those numbers and the older engines were pushed onto a duplicate list with the addition of 20000 to their numbers. Usually this was only for a maximum of a few years until withdrawal. Under BR 2xxxx LMS numbers were changed into 58xxx numbers so as not to transgress into the 6xxxx ex-LNER block.