Why were re-engined 73's numbered 73/9 and not a new class?

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delt1c

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When re engined class 21 became 29, 30 became 31, 48 became 47, 47 became 57 and 56 will become 69.

Why then were the re-engined 73's numbered 73/9 and not a new class?

I can understand the experimental 37 and 47 given a sub class.
 
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DB

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There's not really any logic in it - the rebuild of the 73s was more extensive than the 57s which did get a new class - and the Derby and Brush rebuilt 73s are very different to each other as well as to the original locos.

HSTs - some were put into new new sub-classes when they had MTU engines installed, some weren't. No logic there either.
 

jopsuk

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Because a lot of class numbering is up to whatever the manufacturer/operator feels like, within the overall quite loose structure. With the 73s it's even more confusing as the Network Rail and GBRF/Sleeper versions of the 73/9 have completely different prime movers, not at all related- the GBRF ones have a single big MTU unit, whilst the Network Rail ones have a pair of QSK19s
 

HSTEd

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Are all the 73s still fitted with the original multiple working equipment?
 

DB

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Are all the 73s still fitted with the original multiple working equipment?

The rebuilt ones (both types) all have AAR which the original locos don't have. So far as I am aware the Derby ones don't have anything else. The GBRF first batch (and I think the second) also retain the SR system as fitted to the original locos, but not Blue Star which the original locos also all have.
 

Wyrleybart

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To bring a new class into service on Network Rail costs wonga. You need all kinds of paperwork from professional bodies. Far cheaper just to renumber with the existing classification, also for competency too.

Interestingly though GBRf have decided to declare a new class for 69 instead of 56/whatever
 

birchesgreen

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I read once there was some talk of using Class 75 for the rebuilds. What i don't get is why two separate kinds of rebuilds with different engines and equipment are lumped in the same sub-class.
 

61653 HTAFC

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The bit about all this that slightly irks me is the apparent fondness for using the /9 subclass for almost everything. Particularly with the rebuilt 73s as per this thread, but also things like hybrid 3-car 158s, when there are already 10 158/9s (the West Yorkshire units which differ from the others by having one fewer toilet). Once you get to /9, there's nowhere left to go!

It's particularly irksome with 73s, as the numbers at the start of the 9** series had already been used by the handful of locomotives that used to work on Merseyside.
 

43096

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The bit about all this that slightly irks me is the apparent fondness for using the /9 subclass for almost everything. Particularly with the rebuilt 73s as per this thread, but also things like hybrid 3-car 158s, when there are already 10 158/9s (the West Yorkshire units which differ from the others by having one fewer toilet). Once you get to /9, there's nowhere left to go!

It's particularly irksome with 73s, as the numbers at the start of the 9** series had already been used by the handful of locomotives that used to work on Merseyside.
Bear in mind that some of the other 73xxx range numbers are in use for EMU vehicles, particularly GTR 377s from memory.
 

jopsuk

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Bear in mind that some of the other 73xxx range numbers are in use for EMU vehicles, particularly GTR 377s from memory.
which is a frankly unfortunate restriction of the elderly programming underpinning TOPS. Would be far better if MU vehicles were 8 digit numbers, simply a 01, 02 etc on the end of the unit number
 

43096

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which is a frankly unfortunate restriction of the elderly programming underpinning TOPS. Would be far better if MU vehicles were 8 digit numbers, simply a 01, 02 etc on the end of the unit number
We now have the six digit number scheme for new MU vehicles. I agree, some sort of 7* or 8 digit number including the set number and the position in the set has a lot of sense to it.

* 7 digit gives the benefit that it fits with the EVN system where there's 7 digits available apart from the vehicle type code and country code: i.e. 94 70 xxxx xxx-c
 

norbitonflyer

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I read once there was some talk of using Class 75 for the rebuilds. What i don't get is why two separate kinds of rebuilds with different engines and equipment are lumped in the same sub-class.
Or, given that they are now primarily used as Type 3 diesels, of 1500hp and 1600hp respectively, why not use the never-before-used classes 32 and 34? (Fitting between classes 31 (1470hp), 33 (1550hp), and 35 (1700hp))
 

jopsuk

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We now have the six digit number scheme for new MU vehicles. I agree, some sort of 7* or 8 digit number including the set number and the position in the set has a lot of sense to it.

* 7 digit gives the benefit that it fits with the EVN system where there's 7 digits available apart from the vehicle type code and country code: i.e. 94 70 xxxx xxx-c
seven digit doesn't work for class 390s or 700s!
 

Master29

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The bit about all this that slightly irks me is the apparent fondness for using the /9 subclass for almost everything. Particularly with the rebuilt 73s as per this thread, but also things like hybrid 3-car 158s, when there are already 10 158/9s (the West Yorkshire units which differ from the others by having one fewer toilet). Once you get to /9, there's nowhere left to go!

It's particularly irksome with 73s, as the numbers at the start of the 9** series had already been used by the handful of locomotives that used to work on Merseyside.
That seems to be the case with Airliners too although it may just be unrelated. Boeing 787 9 and Airbus A 350 9 rather than starting at the more obvious 0 or 1. It might be a marketing ploy that has somehow spilled over to the railways but with little point considering the ages of the vehicles in question.
 

D365

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Interestingly though GBRf have decided to declare a new class for 69 instead of 56/whatever
The Class 69 rebuild is more comprehensive than the Class 57 ever was. Aside from bodyshell, motors and bogies, the 69s are brand new.
 

Western Lord

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That seems to be the case with Airliners too although it may just be unrelated. Boeing 787 9 and Airbus A 350 9 rather than starting at the more obvious 0 or 1. It might be a marketing ploy that has somehow spilled over to the railways but with little point considering the ages of the vehicles in question.
In the airliner world, manufacturers have become fixated with the number "8", because, apparently, it is considered lucky in some far eastern cultures (especially China). Thus all new airliners start with the 800 series, or dash-8, and subsequent developments go on from there. This was also the reason that Airbus jumped from A340 to A380 for their "superjumbo" (which also started as the A380-800). Boeing were lucky that the next number in their series was 787, which model starts with the baseline -8. I have a vision of a new company being set up called Eightplanes, with their new 888-800 model, hopefully selling more than eight. There was already a move away from baseline models being called -100, with the Boeing 767 and 777 starting at -200.
 

YorksLad12

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In the airliner world, manufacturers have become fixated with the number "8", because, apparently, it is considered lucky in some far eastern cultures (especially China). Thus all new airliners start with the 800 series, or dash-8, and subsequent developments go on from there. This was also the reason that Airbus jumped from A340 to A380 for their "superjumbo" (which also started as the A380-800). Boeing were lucky that the next number in their series was 787, which model starts with the baseline -8. I have a vision of a new company being set up called Eightplanes, with their new 888-800 model, hopefully selling more than eight. There was already a move away from baseline models being called -100, with the Boeing 767 and 777 starting at -200.
I have a dim memory of cars/motorsport doing something similar. You never have a model that's "-1" as it's doomed to failure. I think they also avoided "01" for the year 2001, for the same superstitious reason.
 

XAM2175

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Because a lot of class numbering is up to whatever the manufacturer/operator feels like, within the overall quite loose structure.
I don't believe this is the reason, but if you take the numbering standard at its letter you'll find it says that "existing electro-diesel locomotives" can only be class 73. :D

To bring a new class into service on Network Rail costs wonga. You need all kinds of paperwork from professional bodies. Far cheaper just to renumber with the existing classification, also for competency too.

Interestingly though GBRf have decided to declare a new class for 69 instead of 56/whatever
Are you quite sure about this? Surely the decision to allocate a new subclass rather than a new class (and the extent of new approval required) would be determined by the amount and nature of change to the vehicle?

We now have the six digit number scheme for new MU vehicles. I agree, some sort of 7* or 8 digit number including the set number and the position in the set has a lot of sense to it.
The numbering standard already allocates 7-digit vehicle numbers - we just don't see the leading zero/es in TOPS and on vehicles that don't display the full EVN. I agree though that an SBB-style system that combines the unit number and vehicle position would have been a nice change.
 

DB

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Are you quite sure about this? Surely the decision to allocate a new subclass rather than a new class (and the extent of new approval required) would be determined by the amount and nature of change to the vehicle?

That's not what happens in practice - the rebuild of the 73s (both versions) was much more extensive than the 57s, but the former didn't get a new class whereas the latter did.
 

XAM2175

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That's not what happens in practice - the rebuild of the 73s (both versions) was much more extensive than the 57s, but the former didn't get a new class whereas the latter did.
True, but I presume that the idea of "we changed absolutely everything about the loco but kept the same class number so you don't need to approve it anew" is as unlikely as it sounds?
 

Wyrleybart

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True, but I presume that the idea of "we changed absolutely everything about the loco but kept the same class number so you don't need to approve it anew" is as unlikely as it sounds?
Can you think of any other reason ?

In the airliner world, manufacturers have become fixated with the number "8", because, apparently, it is considered lucky in some far eastern cultures (especially China). Thus all new airliners start with the 800 series, or dash-8, and subsequent developments go on from there. This was also the reason that Airbus jumped from A340 to A380 for their "superjumbo" (which also started as the A380-800). Boeing were lucky that the next number in their series was 787, which model starts with the baseline -8. I have a vision of a new company being set up called Eightplanes, with their new 888-800 model, hopefully selling more than eight. There was already a move away from baseline models being called -100, with the Boeing 767 and 777 starting at -200.
That isn't strictly correct in terms of the Dash 8. That was simply the next designation after the Dash 6 Otter, and the four engined Dash 7. The two engined Dash 8 was the next designation available and was significantly different to be "reclassed".

Regarding the A380 - that was just a step away from thr A300 A310 A320 A330 A340 and A350 product lines surely ? Obviously 320 saw 319 and 318 and 321 variants which were sufficiently different not to be suffixes like -311 etc.
 
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XAM2175

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Can you think of any other reason ?
I'm thinking that there's a line somewhere that defines the point at which modifications to an existing type-approved vehicle are major enough to warrant recertification, and that that line isn't the class number.

That isn't strictly correct in terms of the Dash 8. That was simply the next designation after the Dash 6 Otter, and the four engined Dash 7. The two engined Dash 8 was the next designation available and was significantly different to be "reclassed".
I suspect that @Western Lord was referring to Boeing's change from 7x7-800 to 7x7-8 ("dash-8"), rather than the de Havilland Canada DHC-7 and DHC-8 which were indeed marketed as the "Dash 7" and "Dash 8" respectively. In more recent times however Bombardier had taken to referring to the latest DHC-8 model as the "Q400" and nothing more.
 

DB

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I'm thinking that there's a line somewhere that defines the point at which modifications to an existing type-approved vehicle are major enough to warrant recertification, and that that line isn't the class number.

That's clearly not the case in practice - as I pointed out above, the 47 to 57 rebuild was less extensive than the two (very different) Class 73 rebuilds. The 57 got a new class, whereas the 73 didn't - and really, the two alternative rebuilds of 73 sare so different both from the original and from each other that each is more logically deserving of its own class than the 57 was.
 

XAM2175

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That's clearly not the case in practice - as I pointed out above, the 47 to 57 rebuild was less extensive than the two (very different) Class 73 rebuilds. The 57 got a new class, whereas the 73 didn't - and really, the two alternative rebuilds of 73 sare so different both from the original and from each other that each is more logically deserving of its own class than the 57 was.
I fear I'm being misunderstood. I understand that the other locos have been reclassed after smaller rebuilds than the 73/9s received. My question is around the premise in #7 - that keeping the same class number obviates the need for recertification. To what extent, if any, is this true?
 

Liverpool 507

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Do the 73/9's still have third rail capability?
Yes they do. The GBRf and Network Rail 73’s have their shoes lowered when visiting the Merseyrail network on PLPR test trains.

The GBRf Caledonian Sleeper 73’s also still have them, but they are raised when not in use (Obviously not in Scotland).
 
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