Turbostar Numbering

[Crossforth]

I was just looking through the specs of the 172 on Wikipedia and it showed the numbering and this struck me as odd:

Class-------Unit nos.
Class 172/0 172001-172008
Class 172/1 172101-172104
Class 172/2 172211-172222
Class 172/3 172331-172345

The numbering of the first two sub classes I understand but the it gets to the 172/2s. Why does it start at 172211 and not 172201?

Again with the 172/3s, why start with 172301 rather than 172331?

I then went on to look at the sub classes of 170.

170/1s; seem normal
170/2s; 201-208, 270-273 - why not just have 201 to 211? I understand there was 3 years between there construction but still, it shouldn't affect how they are numbered as they are both in the same sub class.

All the other sub classes and class 171/7s seem to be rather random and what I want to know is why

 

[The_Stig]

320's are 320 3xx,

318's are 318 2xx

314's are 314 2xx

322's are 322 4xx.

Basically I have no idea, sorry.

 

[90019]

322's are 322 4xx.

481-485

 

[Crossforth]

481-485

Another example, why not 322 401 - 405?

 

[mumrar]

It maybe to do with the vehicle numbers, so that they don't clash with the 170/2 and 170/3 numbers already built. However, that doesn't explain how they overlap with 170/1s though.

This is a totally unresearched guess.

 

[klewer]

It maybe to do with the vehicle numbers, so that they don't clash with the 170/2 and 170/3 numbers already built. However, that doesn't explain how they overlap with 170/1s though.

This is a totally unresearched guess.

The Class 317/1 fleet were renumbered from 3173xx to 3175xx when they were transferred to Ilford from Hornsey - this was to avoid their last three digits from clashing with the Class 321/3 fleet that's also based there.

Maybe the 170/172 fleets were numbered as they are for the same reason?

 

[Failed Unit]

The Class 317/1 fleet were renumbered from 3173xx to 3175xx when they were transferred to Ilford from Hornsey - this was to avoid their last three digits from clashing with the Class 321/3 fleet that's also based there.

Maybe the 170/172 fleets were numbered as they are for the same reason?

There was a bit of that with the 170's - as built

170/1 MML (over to CT)
170/2 Anglia
170/3 Stagecoach and odd builds (HT and spot hire which went to CT)
170/4 Scotrail, 170401-434 (first class) 170450-461 (no first class), 170470-478 SPT. Now of course 450 - 455 have first class and I guess once they are refreshed and repainted their will be no diffence between the standard class units (SPT only have on cycle area whereas the scotrail standard only units have 2)
170/5 CT 2 car
170/6 CT 3 car

CT should have had the 170/3 as they were the 3rd company to order they ask for the 5/6 range so they could identify numbers quickly. The would just refer to a unit as 101 so at the time the CT fleet was as below.

001 - Prototype sprinter
101 - Mk1 Sprinter
212 - Mk2 Sprinter
376 - 153
401 - 156
501 - Turbo
633 - Turbo
797 - 158
858 - 158

So it worked for them until they got the spot hire units, although they didn't have 2x 398's it didn't conflict directly with any 153's

Not sure why HT's units were built as 170/3 rather than 170/8, it was not as if the spec was anything like the other 170/3's. The likes of 170397 were built with no customer in mind so could have ended up sat in siding, unlikely but possible.

When CT aquired the 170/1 then along came the number conflict with the 150/1. I am sure that depots had the "101 is due in for a c6", "What class is that so I can prepare the correct parts"

 

[sprinterguy]

The London Midland class 172/2s and 172/3s are numbered as they are so that the numbers do not duplicte each other within the 172 class, and so that they remain "in sequence" in case of any future sub class renumbering: For example, say if LM units 172220-222 and 172331-335 all had some sort of modification and were renumbered into the 172/4 sub class, then they'd take the numbers 172420-422 and 172431-435, so, no overlap between renumbered two car and three car units.

The reason there is a gap between 172222 and 172331 is so that the 3 car units can start their sub class with a "1". Presumably, the LO 172/0s follow the same numbering scheme, as they take up 172001-008. I wonder if it's some sort of contingency in case the GOBLIN ever gets electrified and the LO 172s go to London Midland? The Chiltern 172s seem to be the odd ones out numerically here.

Similarly with LMs' (formerly Central Trains) 170/5 and 170/6 units, they are numbered so that the final two numbers of each sub class do not overlap. As well as avoiding overlaps with other classes as mentioned above.

There is no 170/7 or 170/8 sub class, as these sub classes are occupied by the similar 171/7 and 171/8 units.

London Overgrounds' various 378 sub-classes are the same; the 378/0, 378/1 and 378/2 sub class number series' do not overlap to allow easy renumbering between sub classes.

The reason there are so many different class 170 sub classes is because every operator has been designated a different sub-class for their fleet. 170270-273 are numbered as they are because they are two car units whilst 170201-208 are three car units, so they want to be kept seperate for rostering reasons.

I have no idea why the 322s are numbered as they are, and to be honest, I've never understood why they couldn't just be another sub class of class 321!

 

[DavidBusDriver]

Class 319's are also numbered similarly, can't remember the exact numbers but I think these are right...

Originally built :

Class 319/0 : 319001 - 060
Class 319/1 : 319161 - 186

The reason the /1's were done as such allowed the current numbering to be established with various sub-classes, but the last two digits still indicates whichever unit it was built as, if you get what I mean!

 

[swt_passenger]

The whole theory goes out the window as soon as you get a class of more than 100 units anyway.

450001 - 450127 were all built as 450s, so 450100 - 127 are still 450/0s as far as I can see. So to conform with railway norms I guess there won't ever be a 450/1 subclass.

(I realise there would have been 450/1s prior to the conversion of them into 350s, but in that case there would have been less than 100 450/0s built.)