Why do LNER Azuma trains have carriages A,B,C,G,H,J,K,L & M

[Willie Bee]

I saw at my local station the other day an LNER Azuma train and noticed there are no carriages D, E & F

I can understand having no I, but why do the trains go A B C G H J K L M ?

I'm travelling to Edinburgh in a couple of week's time and have a seat booked in coach G, which I would have assumed to be near the rear of the train .. as it is, it's nearer the front .. assuming the front is A

 

[JonathanH]

I can understand having no I, but why do the trains go A B C G H J K L M ?

It enables the letters to cope with substitutions of 5-car+5-car formations with 9-car formations, and vice versa.

 

[DanNCL]

Coaches D and E contain first class and only appear on the five car units. Coach F is a standard driving vehicle which only appears in 10 car formations. 10 car formations skip coaches J and L, so a 10 car set (2x 5 cars) is formed A-B-C-D-E-F-G-H-K-M. Doing it this way allows each coach letter to have the same (or very similar) seating layouts regardless whether a 5, 9 or 10 car 80x is allocated.

For reference:
Coach A - Standard Driving Trailer (all units)
Coach B - Standard Motor (all units)
Coach C - Standard Motor (all units)
Coach D - Composite Motor (5/10 car only)
Coach E - First Driving Trailer (5/10 car only)
Coach F - Standard Driving Trailer (10 car only)
Coach G - Standard Motor (10 car)/Trailer (9 car) (9 and 10 car only)
Coach H - Standard Motor (9 and 10 car only)
Coach J - Standard Trailer (9 car only)
Coach K - Composite Motor (9 and 10 car only)
Coach L - First Motor (9 car only)
Coach M - First Driving Trailer (9 and 10 car only)

 

[YorksLad12]

As someone who does (did) cat & class, it's a very effective system. It's the real reason we can't extend the 5-car sets to 7

 

[TT-ONR-NRN]

Out of interest what is the opposition to “Coach I?” Too similar to 1?

 

[DanNCL]

Out of interest what is the opposition to “Coach I?” Too similar to 1?

Yes, although it's not completely unused in the UK as XC use it on paired up voyagers.

 

[TreacleMiller]

Then to confuse matters, the TMS system shows the Individual number and the bodyside cameras refer to them as 1-9 1-5 or 1-10 respectively. Helpful.

 

[2192]

Coaches D and E contain first class and only appear on the five car units. Coach F is a standard driving vehicle which only appears in 10 car formations. 10 car formations skip coaches J and L, so a 10 car set (2x 5 cars) is formed A-B-C-D-E-F-G-H-K-M. Doing it this way allows each coach letter to have the same (or very similar) seating layouts regardless whether a 5, 9 or 10 car 80x is allocated.

For reference:
Coach A - Standard Driving Trailer (all units)
Coach B - Standard Motor (all units)
Coach C - Standard Motor (all units)
Coach D - Composite Motor (5/10 car only)
Coach E - First Driving Trailer (5/10 car only)
Coach F - Standard Driving Trailer (10 car only)
Coach G - Standard Motor (10 car)/Trailer (9 car) (9 and 10 car only)
Coach H - Standard Motor (9 and 10 car only)
Coach J - Standard Trailer (9 car only)
Coach K - Composite Motor (9 and 10 car only)
Coach L - First Motor (9 car only)
Coach M - First Driving Trailer (9 and 10 car only)

Do East Midlands train use the same system on their existing trains Derby - St Pancras?

 

[LNW-GW Joint]

Avanti use the same-ish system for 5-car Voyagers when doubled up to 10.
Pendolinos have extra coaches F and U (unreserved) for the 11-cars compared to the 9-car.
No doubt 5-car 805s will mirror the Voyager layout. We'll have to see what they do with the 7-car 807s.

 

[Benjwri]

the TMS system shows the Individual number

That's far more useful from an operational standpoint to locate faults etc though.

 

[hexagon789]

We'll have to see what they do with the 7-car 807s.

I'd suggest mimic the Pendolinos but miss out some letters. Could be completely wrong though.

 

[43055]

Do East Midlands train use the same system on their existing trains Derby - St Pancras?

If it is still the same then it is the following on the 222's:
A - Standard End (all)
B - Standard (all)
C - Standard (all)
D - Standard (7car), Composite (5/10 car)
E - not used was 5th Standard coach on HST when they were around
F - First (7 car)
G - First (7car), First End (5/10 car)
H - First End (7 car)
J - First End (10 car)
K - Composite (10 car)
L - Standard (10 car)
M - Standard (10 car)
N - Standard End (10 car)

 

[TreacleMiller]

That's far more useful from an operational standpoint to locate faults etc though.

It really isn't... we have 3 systems showing different information.

 

[Benjwri]

It really isn't... we have 3 systems showing different information.

Talking specifically about the TMS showing carriage numbers. It's far more useful in the depot, when the train might be powered down, to have a specific carriage number for a fault occurring, rather than a letter that has to be counted from the correct end of the train, skipping the correct letters, and which makes sure you have the right train. Yet a carriage number would be useless to the public, in that case it is needed to have two different standards. I can't talk for the third.

 

[TreacleMiller]

Talking specifically about the TMS showing carriage numbers. It's far more useful in the depot, when the train might be powered down, to have a specific carriage number for a fault occurring, rather than a letter that has to be counted from the correct end of the train, skipping the correct letters, and which makes sure you have the right train. Yet a carriage number would be useless to the public, in that case it is needed to have two different standards. I can't talk for the third.

Do you work these?

 

[AJDesiro]

I'd suggest mimic the Pendolinos but miss out some letters. Could be completely wrong though.

Considering the 807s have a formation along the lines of: 5 Standard + First/Standard composite + First, it’d probably make sense to have a formation of: K+F+E+D+C+B+A in the event of a unit swap, partially mimicking the 9 car 390s in terms of first class carriages vs standard carriages, just missing coach H and J. This probably makes the most sense considering an 807 doesn’t have that many less seats in standard than a 390/0.

 

[hexagon789]

Considering the 807s have a formation along the lines of: 5 Standard + First/Standard composite + First, it’d probably make sense to have a formation of: K+F+E+D+C+B+A in the event of a unit swap, partially mimicking the 9 car 390s in terms of first class carriages vs standard carriages, just missing coach H and J. This probably makes the most sense considering an 807 doesn’t have that many less seats in standard than a 390/0.

Something along those lines, yes