Types and Classes

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Inversnecky

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The Class 37 was originally referred to as an ‘English Electric Type 3’, a Class 40 as a ‘English Electric Type 4’.

This seems to work fine if you have ‘types’ from various manufacturers. But wasn’t it rather confusing when you had what are now different classes from the same manufacturer?

I was prompted to ask by reference to the ‘Sulzer Type 2s’ or BRCW Type 2s, which included what are now Classes 24, 25, 26 and 27.

In the preTOPS era, was this level of distinction not as important?

Given the differences, though, in power of the various Sulzer Type 2s, how would planners specify which was needed? Reference to ‘D number’ range?

The Peak Classes 44, 45 and 46 would have had a similar issue, I’d have imagined, all bring ‘Derby Type 4s’.
 
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ac6000cw

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Reference to ‘D number’ range?
Yes, basically.

The loco classes were generally allocated numbers in blocks to make it easier e.g. (off the top of my head) D2xx were today's class 40s, D8xx class 42, D1xxx class 52, D15xx class 47, D90xx Deltics etc.
 

30907

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Somewhere I have a 60s WR WTT which shows a " timing load" for each train - but there was also a sort of grid which "converted" those loads to the different classes of loco. So D455 with a Type 4 meant 300 tons with a Hymek and so on down to a D6300 (fictitious example).
 
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hexagon789

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The Class 37 was originally referred to as an ‘English Electric Type 3’, a Class 40 as a ‘English Electric Type 4’.

This seems to work fine if you have ‘types’ from various manufacturers. But wasn’t it rather confusing when you had what are now different classes from the same manufacturer?

I was prompted to ask by reference to the ‘Sulzer Type 2s’ or BRCW Type 2s, which included what are now Classes 24, 25, 26 and 27.

In the preTOPS era, was this level of distinction not as important?

Given the differences, though, in power of the various Sulzer Type 2s, how would planners specify which was needed? Reference to ‘D number’ range?

The Peak Classes 44, 45 and 46 would have had a similar issue, I’d have imagined, all bring ‘Derby Type 4s’.
The old 'D' numbers could be a bit random, personally I'd have saud reference to manufacturer and power. There were sort of class numbers based on these but they never seen to have been widely used, they appear on the diagram books but you never hear people refer to a Deltic as a Class 33/3 do you?
 

Trackman

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The Class 37 was originally referred to as an ‘English Electric Type 3’, a Class 40 as a ‘English Electric Type 4’.

This seems to work fine if you have ‘types’ from various manufacturers. But wasn’t it rather confusing when you had what are now different classes from the same manufacturer?
Good question, always puzzled me why a class 50 was an English Electric Type 4.
 

marsker

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Good question, always puzzled me why a class 50 was an English Electric Type 4.
It was built by English Electric and was in the Type 4 (2000 -3000hp) power range, Most of us that were around then, understood a English Electric Type 4 to be what became a Class 40, so potential for confusion.
IIRC the loco crews on the East Coast referred to them as "2000s", they, of course never had the Class 50 to deal with.
 

Taunton

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Types 1 to 5 were an early BR classification of locos, by horsepower. The banding was quite broad (1000, 1500, 2000, 3000 hp were the breaks), any more detail was not significant at the time.

There were the usual BR-style heavyweight printed documents which described it all for internal use, but most staff in control offices etc kept an Ian Allan Combined Volume on their desk, which had it all in a much more succinct format!
 

hexagon789

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It was built by English Electric and was in the Type 4 (2000 -3000hp) power range, Most of us that were around then, understood a English Electric Type 4 to be what became a Class 40, so potential for confusion.
IIRC the loco crews on the East Coast referred to them as "2000s", they, of course never had the Class 50 to deal with.
I think the 50s were referred to as D400s to differentiate from other EE Type 4s
 

tbwbear

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Looking at some traffic reports in Modern Railways from 1968, it seems the 50s were referred to there as the EE 2700hp type 4s. It is a bit strange that they had a workable system for Electric locomotives (EM2, AL4 etc..) but a completely haphazard one for Diesels. Reading the traffic reports of the various railway magazines of the 60s is sometimes like decoding, trying to work out what they refer to !
 
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Inversnecky

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Looking at some traffic reports in Modern Railways from 1968, it seems the 50s were referred to there as the EE 2700hp type 4s. It is a bit strange that they had a workable system for Electric locomotives (EM2, AL4 etc..) but a completely haphazard one for Diesels. Reading the traffic reports of the various railway magazines of the 60s is sometimes like decoding, trying to work out what they refer to !

Yes, I was thinking of that but forgot to put it in: the Class 8x electrics all had a separate AL number.
 

delt1c

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The eastern Region had classification codes for diesels. I don't have them to hand but a quick search on the internet should find them.
 
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xotGD

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Perhaps the lack of class identifiers in the pre-TOPS days for diesels prompted people to come up with nicknames?
 

tbwbear

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Also I would be interested to understand if anyone can shed light on it... when the TOPS class number system was created (late 60s) did they already know they were going to renumber ( early 70s) as well ?

In other words - was the move from EE 2700hp D401 through Class 50 no. 401 to 50 001 - pre-planned?

Was it one decision implemented at two separate times or was it two separate decisions made at two separate times ?
 

Clarence Yard

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The class numbering designations pre-dated TOPS. It was done, in part, to try and get some standardisation into identification. The data panels were the first external manifestation of the class numbers.
 

Inversnecky

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In terms of how what we now call classes were referred to in the pre-TOPS 1960s, I was recently watching a 1960s film on YouTube about the new diesel fleet, and the narrator referred to, for example, ‘an English Electric 1800 horsepower’ diesel (iirc), giving the manufacturer name and hp with no reference to type.
 
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hexagon789

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In terms of how what we now call classes were referred to in the pre-TOPS 1960s, I was recently watching a 1960s film on YouTube about the new diesel fleet, and the narrator referred to, for example, ‘an English Electric 1800 horsepower’ diesel (iirc), UDI g manufacturer name and hp with no reference to type.
I think that was standard practice, while there were classification systems of a sort these were on a regional basis and pre-TOPs diagram books simply identify by manufacturer and power output

Yes we called them 400 ers in the Preston Area in the early 1970s
Bit like Westerns being called "Thousands"
 

Inversnecky

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I think that was standard practice, while there were classification systems of a sort these were on a regional basis and pre-TOPs diagram books simply identify by manufacturer and power output


Bit like Westerns being called "Thousands"

I suppose there was no alternatives at the time.

Looking on Wikipedia, there were of course a lot of diesels with the same rating, so I guess the manufacturer label distinguished.
 

alexl92

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The Class 37 was originally referred to as an ‘English Electric Type 3’, a Class 40 as a ‘English Electric Type 4’.

This seems to work fine if you have ‘types’ from various manufacturers. But wasn’t it rather confusing when you had what are now different classes from the same manufacturer?

I was prompted to ask by reference to the ‘Sulzer Type 2s’ or BRCW Type 2s, which included what are now Classes 24, 25, 26 and 27.

In the preTOPS era, was this level of distinction not as important?

Given the differences, though, in power of the various Sulzer Type 2s, how would planners specify which was needed? Reference to ‘D number’ range?

The Peak Classes 44, 45 and 46 would have had a similar issue, I’d have imagined, all bring ‘Derby Type 4s’.
Bear in mind that some steam locomotive classes were referred to by their power class - British Railways 9F, LMS 4F etc. So in some ways, referring to a diesel as an English Electric Type 3 wasn't that different. It was a type 3 loco built by EE. But of course the confusion came when, as has been mentioned, a manufacturer created more than one class of a particular type.
 

hexagon789

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I suppose there was no alternatives at the time.
As I mentioned above, there were classification systems - but they never seemed to catch on perhaps because they were not BR wide, the WR had a system and so did the ER and they weren't compatible.
 

Bevan Price

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As I mentioned above, there were classification systems - but they never seemed to catch on perhaps because they were not BR wide, the WR had a system and so did the ER and they weren't compatible.
I think that the ER system was "edited" at least once, but this is a summary of the version shown in the Ian Allan ABC for 1963.
Basically there were two numbers, in the format XX/YY.
XX indicated the power range (in h.p.). Multiplying XX by 100 gave the power range.
YY was a sub-division to distinguish between different classes in the same power range.

The list is too long to type in full, but here are a few examples:
2/1 (Later Class 03; 204hp)
3/1 (Class 08; 350 hp)
8/5 (Class 15; 800 hp)
10/3 (Class 20; 1000hp)
11/1 (Class 24, D5000-48 only, 1160 hp)
11/1A (Class 24, D5049 upwards, 1160 hp)
11/6 (Class 26, 1160 hp)
12/2 (Class 30, D5500-19, 1250 hp)
13/2 (Class 30, D5520 upwards, 1365 hp)
17/3 (Class 37, only up to D6818 at that time)
25/1 (Class 45; 2500 hp)
25/1A (Class 46)
27/1 (Class 52)
27/2 (Class 47)
33/3 (Class 55)
 

43096

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I think that the ER system was "edited" at least once, but this is a summary of the version shown in the Ian Allan ABC for 1963.
Basically there were two numbers, in the format XX/YY.
XX indicated the power range (in h.p.). Multiplying XX by 100 gave the power range.
YY was a sub-division to distinguish between different classes in the same power range.

The list is too long to type in full, but here are a few examples:
2/1 (Later Class 03; 204hp)
3/1 (Class 08; 350 hp)
8/5 (Class 15; 800 hp)
10/3 (Class 20; 1000hp)
11/1 (Class 24, D5000-48 only, 1160 hp)
11/1A (Class 24, D5049 upwards, 1160 hp)
11/6 (Class 26, 1160 hp)
12/2 (Class 30, D5500-19, 1250 hp)
13/2 (Class 30, D5520 upwards, 1365 hp)
17/3 (Class 37, only up to D6818 at that time)
25/1 (Class 45; 2500 hp)
25/1A (Class 46)
27/1 (Class 52)
27/2 (Class 47)
33/3 (Class 55)
That looks to me that the first character after the / indicated the builder - so 1 was BR workshops, 2 was Brush, 3 English Electric etc.
 

hexagon789

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I think that the ER system was "edited" at least once, but this is a summary of the version shown in the Ian Allan ABC for 1963.
Basically there were two numbers, in the format XX/YY.
XX indicated the power range (in h.p.). Multiplying XX by 100 gave the power range.
YY was a sub-division to distinguish between different classes in the same power range.

The list is too long to type in full, but here are a few examples:
2/1 (Later Class 03; 204hp)
3/1 (Class 08; 350 hp)
8/5 (Class 15; 800 hp)
10/3 (Class 20; 1000hp)
11/1 (Class 24, D5000-48 only, 1160 hp)
11/1A (Class 24, D5049 upwards, 1160 hp)
11/6 (Class 26, 1160 hp)
12/2 (Class 30, D5500-19, 1250 hp)
13/2 (Class 30, D5520 upwards, 1365 hp)
17/3 (Class 37, only up to D6818 at that time)
25/1 (Class 45; 2500 hp)
25/1A (Class 46)
27/1 (Class 52)
27/2 (Class 47)
33/3 (Class 55)
I understood the second number referred to manufacturer rather than just being to subdivide power types:

1 was BR
2 was Brush
3 was English Electric
4 was North British
5 was Met Vick
6 was BRCW

And so on.

A letter after the second number was used to subdivide variants - thus a Class 21 - 1100hp, North British (electric transmission) was 11/4 while a Class 22 - also 1100hp & Nth British but with hydraulic transmission was 11/4A. A Class 33 was 15/6 while the narrower 'Hastings' variant was 15/6A
 

Bevan Price

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I understood the second number referred to manufacturer rather than just being to subdivide power types:

1 was BR
2 was Brush
3 was English Electric
4 was North British
5 was Met Vick
6 was BRCW

And so on.

A letter after the second number was used to subdivide variants - thus a Class 21 - 1100hp, North British (electric transmission) was 11/4 while a Class 22 - also 1100hp & Nth British but with hydraulic transmission was 11/4A. A Class 33 was 15/6 while the narrower 'Hastings' variant was 15/6A
Yes, looking at the list, that does seem to be correct, and it would make the other builders' numbers to be:
7: Beyer Peacock
8: LMSR
9: SR
10: LNER
11: GWR
12: Barclay
13: Drewry
14: Hudswell-Clarke
15: Hunslet
16: Ruston & Hornsby
17: Yorkshire Engine Co
18: Clayton
 

hexagon789

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Yes, looking at the list, that does seem to be correct, and it would make the other builders' numbers to be:
7: Beyer Peacock
8: LMSR
9: SR
10: LNER
11: GWR
12: Barclay
13: Drewry
14: Hudswell-Clarke
15: Hunslet
16: Ruston & Hornsby
17: Yorkshire Engine Co
18: Clayton
Perhaps not the most straightforward of systems but presumably it fulfilled a purpose at the time as a manner of abbreviating the identifying feature of locomotive types
 

hexagon789

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Makes you appreciate the TOPS classes!
I'd say so, while it's not perfect and you don't have the same simpler power identifier - the first digit being power class (as in Type 1 to Type 5) rather than the actual hp figure, but it's generally more straightforward having just the two digits loco classes in my view
 

Inversnecky

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Within the TOPS classes, after getting in the right group of ten based on power, was it a matter of a new loco just taking the next number up? Or higher range ones choosing a higher number?
 

hexagon789

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Within the TOPS classes, after getting in the right group of ten based on power, was it a matter of a new loco just taking the next number up? Or higher range ones choosing a higher number?
There is a sort of pattern of increasing power as you go up the classes within the 'Type' blocks, but then many locos don't fit exactly into the block the power output might suggest and more recently classes (Class 57s for instance) are numbered based on hauling power equivalent to the old system rather than pure power output. A 57 is 2,500 or 2,750hp but is treated as a Type 5 because its upgrade from a 47 apparently now allows it to haul the same loads but with performance equivalent to a Type 5. Whether that is true in practice though...
 

xotGD

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Within the TOPS classes, after getting in the right group of ten based on power, was it a matter of a new loco just taking the next number up? Or higher range ones choosing a higher number?
A Class 31 has a number starting with a '3', is classified as a Type 2, but has the haulage capability of a Type 1 (on a good day).

(Soz to any Ped fans out there :smile: )
 
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