Why Do the MK4s Switch Layout in the Middle?

[whhistle]

Why in First Class do MK4s switch layout in the middle of the coach?

The single seats start on one side of the coach but switch about half way down so they're on the other side with a large space (for dancing?) in the middle.

In addition, why do they have a glass partition about a third from the end?

 

[The_Engineer]

All part of the original design concept. The glass partitions are to break up the sight lines to make it appear less open. The cross-over likewise, and gave an area to pass trolleys, etc.

 

[Ianno87]

Does it also help balance out the weight distribution of the coach?

 

[The_Engineer]

Does it also help balance out the weight distribution of the coach?

I don't think that was an issue, as the chicane appeared as a pink-tie concept sketch before engineers got their hands on the design. It may have had some benefit though!

 

[edwin_m]

I remember being worried the first time I flew (BAC-111 I think, age about 8) that the 3+2 seating meant the plane would be unbalanced and would spiral down to a grim fate. The fact I'm here to write this shows that didn't happen, and the Mk3s seem to have got by with 2+1 in First as well as both toilets on the same side.

 

[AndrewE]

I don't know if it was intended, but the result is that people wanting either single or pairs of seats have a choice of the shady side, equally the side with the best view. Doesn't work like that on Pendolinos... at least with loco-hauled Mk 3s there is a chance of a mixture of coach orientations!

 

[Ianno87]

I remember being worried the first time I flew (BAC-111 I think, age about 8) that the 3+2 seating meant the plane would be unbalanced and would spiral down to a grim fate. The fact I'm here to write this shows that didn't happen, and the Mk3s seem to have got by with 2+1 in First as well as both toilets on the same side.

I'm not suggesting it's impending doom if the thing isn't balanced; it might just made a marginal difference to evenness of wear and tear on the bogies/suspension... (I'm not an engineer)

 

[43096]

I'm not suggesting it's impending doom if the thing isn't balanced; it might just made a marginal difference to evenness of wear and tear on the bogies/suspension... (I'm not an engineer)

It is very marginal at best. For Mark 3s there are different bogie setups for different vehicle types, which can be (and are in some cases) different at each end of the vehicle. Underframe equipment makes a far bigger difference than the seating layout - just as an example, whether a motor alternator set is fitted (or, indeed, which type of motor alternator it is) affects the type of suspension setup used.

 

[AM9]

I'm not suggesting it's impending doom if the thing isn't balanced; it might just made a marginal difference to evenness of wear and tear on the bogies/suspension... (I'm not an engineer)

I doubt whether it would even be noticeable. If the whole coach was 2+1 on the same side along it's length that would mean that those 16 passengers (with a notional weight of (say) 90Kg) would be about 1440Kg at 300mm off the centreline of the vehicle. The vehicle weighs about 40t including bogies so maybe the body is about 20t+. The body is compliantly mounted on bolsters that distribute the weight laterally.
Given that the MKIV sets generally run most of the time N-S without turning, I suspect that repeated running over set track formations at specific speeds would put more of an irregular wear pattern than any combination of first class passenger loads.

 

[AndrewE]

with 16 seats alongside the gangway on 1 side (for a MkIII, which is "unbalanced" all the way through)... I see AM9 has beaten me to it!

 

[FQTV]

All part of the original design concept. The glass partitions are to break up the sight lines to make it appear less open. The cross-over likewise, and gave an area to pass trolleys, etc.

None of the original partitions as-built remain.

Coach 'M's do retain, however, the side partitions which latterly formed the separator between the last stand of Smoking and non-Smoking accommodation.

The door across the aisle between the two panels was removed when Smoking accommodation was withdrawn.

Coach 'K's and 'L's have no partitions of any kind.

 

[Warwick]

The same unbalanced theory could be offered for the old locomotive hauled slam door coaches with eight compartments to one side.

 

[AM9]

The same unbalanced theory could be offered for the old locomotive hauled slam door coaches with eight compartments to one side.

Average passenger weight* is minute compared with the tare weight of the body.

* the average passenger load is far removed from the coach's full capacity, - especially in 1st class.

 

[Helvellyn]

You can see the original partitions in this photo. Lots of smoked glass and greys! If I recall correctly the partitions split the coach into three sections and the chicane helped break the coach up even more, given First Class a more exclusive/private feel.

http://www.khurramhashmi.org/crbasic_info/images/htt-46-1.jpg

None of the original partitions as-built remain.

Coach 'M's do retain, however, the side partitions which latterly formed the separator between the last stand of Smoking and non-Smoking accommodation.

The door across the aisle between the two panels was removed when Smoking accommodation was withdrawn.

Coach 'K's and 'L's have no partitions of any kind.

Actually, 'K' does where the single bay next to the kitchen was removed to provide storage for the complimentary First Class offering, with two Standard Class seats also provided for staff. An internal power sliding door separates this area from the rest of the coach.

 

[FQTV]

Actually, 'K' does where the single bay next to the kitchen was removed to provide storage for the complimentary First Class offering, with two Standard Class seats also provided for staff. An internal power sliding door separates this area from the rest of the coach.

You're quite right; there is a separator there now too but, again, it's not original or as-built.

As you say, it was fitted specifically for the crew seats and additional servery/storage.

And, of course, when first introduced and until GNER's time, Coach 'H' ran the other way around (as HST Coach 'J' still does with LNER) such that First was three and a half carriages. The current Coach 'K' servery would therefore have been marooned had it been in the original consist.

 

[BelleIsle]

Central partitions are not a new idea. One of the downsides of moving non-suburban coaches from side compartments to open saloons was you were no longer insulated from noise and drafts from the doors, smells from the toliets etc. The Mk2b resolved this by creating vestibules at either end and sealing off the saloon with interior doors (like most long distance trains today). This necesitated the removal of the centre doors. Worried that people would fell exposed by the larger saloon they switched the side of the gangway midway down and put in a luggage rack to break things up.

 

[whhistle]

I guess I'm just surprised if it was that good, why they don't do it with new build stock now.
Then again, I guess chepaer + able to get more seats in play a part.

Thank you all.

 

[duffield]

I always make a beeline for the two-seat at the switchover point on MK4s. Gives you tons of room (e.g. you can have a largish bag in the space behind the adjacent seat which you can access freely without it being at all in anyone's way).
I'm hoping the rumours are true about us getting them as a stop-gap for PRM compliance on the MML until the bi-modes arrive (which could easily mean we'd have them for five years!).
I can't easily find it but there was a post a few months back on this forum stating that the necessary electrical compatibility mods to make them work with HST power cars were 'being designed'. Don't suppose anyone's heard anything further about this?