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A Formula For Window Alignment?

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Rhydgaled

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Most trains seem to have at least a few seats where your view is at least partly blocked by a window pillar. So, I have wondered whether it is possible to ensure that every seat has a good view (unless it's night time or the train is in a dark tunnel of course). Also, if having every seat aligned is the aim, bays of four around a table just don't work in a class 153 because the windows are just too small for it to happen. So how big do the windows need to be for table bays to work, and what is the optimum seat pitch for airline-style seating on a class 153?

Now, I wouldn't say maths is one of my strong points but somehow I've come up with this:
B = 2x (P = W + D)
Where B is the bay pitch (seat back to seat back), P is the (airline) seat pitch, W is the window width and D is the width of the window deadspace (pillar). For the avoidance of doubt, here's a diagram of those dimensions:
Window Alignment Diagram.PNG
It is clear that large values of D would impact the view to some extent, but is that just a maximum value needs to be set for D or should thickness of the seat back be added as a variable? Can anyone see any other problems with this possible formula?
 
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Roast Veg

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Your formula promotes lots of tiny windows, kind of like an aircraft, which would be very expensive to design and maintain. Additionally, you seem to be overlooking the fact that seats at the end of the train will be flush with the ends of the carriage interior.

In principle, B = 2P is a very convenient simplification, but different seats and tables are of different sizes.
 

ash39

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Looks good until you need to allow for things like luggage racks, doors, toilets. Then the added pressure to fill every available space with seating and that's why we end up with sub-optimal alignment.

If it was as simple as working to a formula, every train would have perfect alignment.
 

xotGD

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The people who designed the Mark 1 must have been mathematical geniuses!
 

Harpers Tate

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Or perhaps it's that Mk1 were designed and built with both seats and windows considered together in the dimensions. Rather than (I suspect) body built from standardised parts and then seats "crammed" in as a separate operation. If I remember correctly, the window pitch in First Class was greater than that in second - to match the different seat pitch.

"It's not as simple as......." is usually a euphemism for "it would cost more and we don't care enough to pay up".
 

ijmad

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The people who designed the Mark 1 must have been mathematical geniuses!

Mark 1 was all bay seating, which makes the problem easier.

Sadly we don't have room for that on the modern railway, unless you'd like half your passengers to stand.
 

Xenophon PCDGS

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The people who designed the Mark 1 must have been mathematical geniuses!

I received my First in Mathematics no less than 53 years ago from Manchester University in 1966, but whilst I note the interesting yet theoretical formulaic discussions so far, reality tells me that you will travel on units that your TOC have negotiated interior unit design prior to a unit order being placed.
 

krus_aragon

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It is clear that large values of D would impact the view to some extent, but is that just a maximum value needs to be set for D or should thickness of the seat back be added as a variable? Can anyone see any other problems with this possible formula?

One possible limitation is that it your formula doesn't consider whether the seats are aligned to the windows at the start of the carriage (in other words, whether the windows and seats are "in phase" or not). If the first seat has a pillar for a view, then following your formula will ensure that every seat has a pillar for a view. :frown:

In other words, your formula is a good start, but there are other things that have to be considered too.
 

coppercapped

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Or perhaps it's that Mk1 were designed and built with both seats and windows considered together in the dimensions. Rather than (I suspect) body built from standardised parts and then seats "crammed" in as a separate operation. If I remember correctly, the window pitch in First Class was greater than that in second - to match the different seat pitch.

"It's not as simple as......." is usually a euphemism for "it would cost more and we don't care enough to pay up".
The form of construction of the Mark 1 coach was very different to that of the Mark 2s and later. They were built on a standardised underframe which took all traction and buffing loads, but which came in two lengths, 57 ft and 64ft 6in, on which was built a comparatively light weight steel body. The design of the corridor stock was laid out for three aside 3rd class compartments (four aside for the Western and the Southern Regions) with increased leg room for the first class. This led to eight compartments in a third class (later second class) coach and seven compartments in a first class coach. All the other components, windows, doors, etc. were standardised and the seats were hand built in-situ - I remember seeing coaches being upholstered in the old carriage shops in Swindon.

It was therefore comparatively easy to vary the bodywork as all it meant was that the window openings were cut out of the steel side sheets at different spacings so composites, brake seconds, brake firsts and brake composites were all possible.

With the change to monocoque construction in some Swindon designed and built intercity DMUs followed later by the Mark 2 coach it became more time consuming, in the days before computers, to manually restress the design for differing numbers of window openings and window and door spacings. (The monocoque had safety, weight and cost advantages over a coach with a separate underframe so it was a definite advance). Because of the design effort, the Mark 2 coach was built in a much smaller variety of body designs than the Mark 1 and the Mark 3, although the first design to benefit from computers to do the stressing, essentially only has one body style, that of an eight bay first class coach. The second class seat spacing was from the start always a compromise to get more seats in the same space as in the first class so the seats were always out of phase with the windows.

Having only one body with the seats fixed to rails in the floor does mean that it is much easier to adapt the seating as needs change. Fixing the window openings to the class and arrangement of seats might mean an optimum arrangement when built but will probably not be such a good idea fifteen years later.

To my way of thinking many of the perceived issues with window spacing could be avoided if the deadlights between the window openings could be reduced in length. This may require some more expensive strengthening of the sides between the windows to maintain the body's rigidity and crash-worthiness while keeping the natural bending and twisting frequencies in a suitable range. But I am sure it would be possible.
 

hwl

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The main issue is that you get 7 rows of airline seats for every 6 rows of facing seat (assuming sensible leg room) so I can't see a workable solution.

Seating requirement change over time and some thing as simple as the extra legroom for the priority seats near the doors will completely throw everything.
 

hwl

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Having only one body with the seats fixed to rails in the floor does mean that it is much easier to adapt the seating as needs change. Fixing the window openings to the class and arrangement of seats might mean an optimum arrangement when built but will probably not be such a good idea fifteen years later.
Agreed
To my way of thinking many of the perceived issues with window spacing could be avoided if the deadlights between the window openings could be reduced in length. This may require some more expensive strengthening of the sides between the windows to maintain the body's rigidity and crash-worthiness while keeping the natural bending and twisting frequencies in a suitable range. But I am sure it would be possible.
Not really do-able given the construction method as a side is made using 4 or 5 extruded twin wall planks of Aluminium aligned along the coach length ways that are impingement held and welded together then put on a large milling machine to sort the final dimensionality of all the edgea (inc. door and Window openings). The effect of this construction method is that the webs between the walls are aligned horizontally rather than vertically which then requires a larger gap between windows unless the window lenght and height are reduced than for vertical webs (which are now starter in terms on construction method).
 
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Bletchleyite

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Looks good until you need to allow for things like luggage racks, doors, toilets. Then the added pressure to fill every available space with seating and that's why we end up with sub-optimal alignment.

No, the primary problem is priority seating, which I understand is required to be a certain percentage legroom increase. This is actually really stupid if you observe how people of limited mobility use train seating, and it means that most such people choose not to use priority seats - most such people want to lower themselves into their seat using the seat back in front or the table, which you can't do with extra legroom!

The most sensible thing to do with priority seats would be to give them the same legroom as other seats and position them near to the doors, the toilets and a large luggage rack provision. And to give all seats decent legroom like Class 80x.
 

duffield

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No, the primary problem is priority seating, which I understand is required to be a certain percentage legroom increase. This is actually really stupid if you observe how people of limited mobility use train seating, and it means that most such people choose not to use priority seats - most such people want to lower themselves into their seat using the seat back in front or the table, which you can't do with extra legroom!

The most sensible thing to do with priority seats would be to give them the same legroom as other seats and position them near to the doors, the toilets and a large luggage rack provision. And to give all seats decent legroom like Class 80x.

Having some experience with my late wife and her disabilities (severe knee problems, using walking stick, not wheelchair), the easiest seats for her to sit in were:
Class 158 (Liverpool Norwich) 'open' end carriage seats - where there was plenty of room to walk in, turn round, and sit down (support yourself with stick while sitting down) - and you were right by the toilet. I think these are priority seats.
Voyagers, airline seating in 1st class with lift-up table on outside seat. Not priority seats.
Javelin, class 395 airline seats - again, room to 'walk in' and turn round, support yourself with stick while sitting down.

So extra legroom *can* be helpful to some disabled people, but it needs to be quite a lot to be useful.

Anyhow, I think it varies considerably by train type and journey length. On longer journeys getting in and out the seat to get to the toilet and how close the toilet is, is much more important. On shorter journeys, getting to/from the nearest door quickly is more important.

Short version: It's complicated!
 

Bletchleyite

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So extra legroom *can* be helpful to some disabled people, but it needs to be quite a lot to be useful.

So I guess a bit extra is unhelpful but a lot is helpful?

I guess to deliver what you suggest you could put 3 rows of priority seats in the space of 4 regular window aligned airline rows / 2 regular window aligned table bays, only leaving the centre priority row misaligned?

I only made the observation from personal experience - I tend to sit in priority seats because I have a very long upper leg so need the space - I would give the seat up if someone required it but I don't think this has ever happened, leading me to suspect that they aren't, in their present form, optimal for people with mobility difficulties as if they were such people would surely go straight for them even if other seats were available.
 

AM9

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Given the conflicts of design strength, manufacturing processes, seat allocation and passengers' unpredictable proclivities in seat locations, I think that securing a particular window view from some (or any) seats is well down the list of priorities on a capacity and cash-limited railway.
 

Rhydgaled

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The main issue is that you get 7 rows of airline seats for every 6 rows of facing seat (assuming sensible leg room) so I can't see a workable solution.
Mark 1 was all bay seating, which makes the problem easier.

Sadly we don't have room for that on the modern railway, unless you'd like half your passengers to stand.
Indeed, having only bay seating would make it much easier; if you persist with the idea that you get more airline seating in the same space than you would with bays. That's why the formula is B = 2xP, so that two rows of airline seats take up the same space as a bay. The population is getting taller, on average, so legroom in the airline-style seating needs to be increased anyway. For that reason we also need more carriages so that passengers don't have to stand.

One possible limitation is that it your formula doesn't consider whether the seats are aligned to the windows at the start of the carriage (in other words, whether the windows and seats are "in phase" or not). If the first seat has a pillar for a view, then following your formula will ensure that every seat has a pillar for a view. :frown:
Good point! My intention is that the interior would be designed outwards from the window(s) nearest the centre of the coaches, where there would be bays of seating around tables with the airline-style seating towards (and facing) the carriage ends.

To my way of thinking many of the perceived issues with window spacing could be avoided if the deadlights between the window openings could be reduced in length. This may require some more expensive strengthening of the sides between the windows to maintain the body's rigidity and crash-worthiness while keeping the natural bending and twisting frequencies in a suitable range. But I am sure it would be possible.
Window pillars ('deadlights' as you call them) vary quite a bit in size on existing stock, with the class 195s at around 48cm exceeding the desirable maximum of 450mm given in the Rail Delivery Group's Key Train Requirements, so I imagine that there is some scope for improvement there.

Seating requirement change over time and some thing as simple as the extra legroom for the priority seats near the doors will completely throw everything.
No, the primary problem is priority seating, which I understand is required to be a certain percentage legroom increase. This is actually really stupid if you observe how people of limited mobility use train seating, and it means that most such people choose not to use priority seats - most such people want to lower themselves into their seat using the seat back in front or the table, which you can't do with extra legroom!

The most sensible thing to do with priority seats would be to give them the same legroom as other seats and position them near to the doors, the toilets and a large luggage rack provision. And to give all seats decent legroom like Class 80x.
Is the priority seating really required to have more legroom than the other seats, regardless of how much legroom is generally provided? If so, that is indeed really stupid as the logical solution otherwise is to give everyone priority seat levels of legroom (unless of course the requirement for priority seat minumum legroom is far more than required for able-bodied tall passengers).

In principle, B = 2P is a very convenient simplification, but different seats and tables are of different sizes.
Sorry, I'm not sure I understand. Are you saying the seats used in bays of four around tables are different to the ones used in airline-style arrangements, because I hadn't realised that if so (the Grammer seats one class 158s as refurbished by Arriva Trains Wales for example look the same whether they are around a table or not).

Your formula promotes lots of tiny windows, kind of like an aircraft, which would be very expensive to design and maintain.
How do you define tiny? It's very possible I've written the formula out wrong, because if I've done it right W + D should always be larger than on a class 153 (which does have lots of fairly narrow windows and thus you cannot make bay seats align properly).

Looks good until you need to allow for things like luggage racks, doors, toilets. Then the added pressure to fill every available space with seating and that's why we end up with sub-optimal alignment.
Put all those things at the ends of the carriages and you don't have a problem, at least not with window alignment. Looking at this picture (not mine) of a TPE mark 5 rake it would appear that TPE have decided to do just that and taken it a step further by not putting windows in the space the luggage racks occupy.
 

Bletchleyite

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Put all those things at the ends of the carriages and you don't have a problem, at least not with window alignment. Looking at this picture (not mine) of a TPE mark 5 rake it would appear that TPE have decided to do just that and taken it a step further by not putting windows in the space the luggage racks occupy.

And yet the TPE Mk5 follows the dire Class 195 in having almost no seats aligned to the windows due to sheer laziness of design. The WCML EMUs are the only new UK CAF units which will have good alignment.
 

mmh

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The non-mathematical answer to this is "the original class 377 driving carriage." Suburban doors-at-thirds body yet still has an all table of 4 layout between the doors perfectly lined up with the windows. The carriage ends are two tables, perfectly aligned, and - even though this is impossible - two rows of airline seats, perfectly aligned.

Is the priority seating really required to have more legroom than the other seats, regardless of how much legroom is generally provided?

I don't think that's correct, simple observation suggests it isn't so I'm not sure how that became a "fact."
 

Bletchleyite

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I don't think that's correct, simple observation suggests it isn't so I'm not sure how that became a "fact."

Can you think of an example of any UK rolling stock in which the priority seats do not have more legroom than the other seats in the same coach, however generous they are? I can't.
 

mmh

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Can you think of an example of any UK rolling stock in which the priority seats do not have more legroom than the other seats in the same coach, however generous they are? I can't.

Classes 455, 458, 313, 375, 376, 377, 378, 387, 390, 507,508

I'll give you that 378s are an unfair example though with their infinite legroom!
 

Bletchleyite

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Classes 455, 458, 313, 375, 376, 377, 378, 387, 390, 507,508

I'll give you that 378s are an unfair example though with their infinite legroom!

I don't know about some of the others, but on the 390 they categorically do have more space, both the airline and the table ones (the table ones additionally have the folding flaps to ease access).

The Southern Electrostars (and SE ones with the same layout) do too - they achieve it by having the priority seats as airline seats with the same spacing as a bay which means the "dead space" that would be behind the seat backs actually goes to additional legroom.
 

mmh

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I don't know about some of the others, but on the 390 they categorically do have more space, both the airline and the table ones (the table ones additionally have the folding flaps to ease access).

The Southern Electrostars (and SE ones with the same layout) do too - they achieve it by having the priority seats as airline seats with the same spacing as a bay which means the "dead space" that would be behind the seat backs actually goes to additional legroom.

Why can't you just accept that sometimes you're wrong? All of those trains have priority seats at the same spacing as non-priority seats. Why would I make this up? What are you trying to win here? This isn't usenet. Sigh.
 

Bletchleyite

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Why can't you just accept that sometimes you're wrong? All of those trains have priority seats at the same spacing as non-priority seats. Why would I make this up? What are you trying to win here? This isn't usenet. Sigh.

Which seats specifically in the 390? I always sit in priority seats in 390s, because they have more legroom than non priority seats.

Does anyone have a copy of the relevant documents (both RVAR and PRM-TSI, because they do differ in some regards) who can confirm what the specification is?

One thing of specific note is that the Class 319s operated by LNR were modified to increase the spacing of the priority seats (slightly reducing the non-priority ones, which was annoying as I used to be able to sit in all seats on that layout and now don't fit the regular seats) - why would LNR have done this were it not necessary?
 
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mmh

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Which seats specifically in the 390? I always sit in priority seats in 390s, because they have more legroom than non priority seats.

I only put class 390 in my list because I knew you'd pick up on it. Thank you. Some of the table seats with the flip up portions are no bigger, and the pair of single seats in coach C certainly don't have any extra legroom.

Now. About all the other classes you think I'm making it up about...
 

coppercapped

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Agreed

Not really do-able given the construction method as a side is made using 4 or 5 extruded twin wall planks of Aluminium aligned along the coach length ways that are impingement held and welded together then put on a large milling machine to sort the final dimensionality of all the edgea (inc. door and Window openings). The effect of this construction method is that the webs between the walls are aligned horizontally rather than vertically which then requires a larger gap between windows unless the window lenght and height are reduced than for vertical webs (which are now starter in terms on construction method).
I appreciate your point about current production methods (of which I am aware), which are applicable to aluminium bodies made of extrusions, but I am not sure that it is such a show stopper as you imply. The Class 165 and 166 DMUs are also built using longitudinal double skinned aluminium extrusions (samples can be seen in the York railway museum) and have very small deadlights, see this image of a Class 166.

In spite of this existing example, engineering considerations were why I suggested that some more expensive strengthening of the sides between the windows may be necessary to reduce the length of the deadlights in future designs.

Reducing the length of the deadlights while maintaining body strength and keeping resonances within a suitable range is an engineering challenge. Finding a solution to meet current regulations will cost money and resources. Depending on the material used for the body, aluminium extrusions or steel (or even wound carbon fibre as now used for large aircraft fuselages and wings!) the design solutions will clearly differ.

Reducing the length of the deadlights with current aluminium construction techniques may be a non-starter, but this does not mean it is impossible in the future.
 

Bletchleyite

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The size of the deadlights doesn't necessarily need to be reduced. The train just needs to be specified so that the windows are roughly aligned to a Standard class bay (which they are in a lot of modern stock), and to align the seats to them - something which Northern have failed to do so in the Class 195 for no sensible reason I can think of.

First Class can then be done by having the bays the width of a window and most of the deadlights on both sides, with a generous row of airline seating in between.
 

Mikey C

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The Networkers (and Network Turbos I think) all had very good seat to window alignment when delivered. Indeed that was one of the design aims when NSE were speccing the design (after the terrible Mk3 EMU layout), the narrow pillars certainly help.
640px-465173_DMSO_Interior.jpg
 

Flying Snail

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The form of construction of the Mark 1 coach was very different to that of the Mark 2s and later. They were built on a standardised underframe which took all traction and buffing loads, but which came in two lengths, 57 ft and 64ft 6in, on which was built a comparatively light weight steel body. The design of the corridor stock was laid out for three aside 3rd class compartments (four aside for the Western and the Southern Regions) with increased leg room for the first class. This led to eight compartments in a third class (later second class) coach and seven compartments in a first class coach. All the other components, windows, doors, etc. were standardised and the seats were hand built in-situ - I remember seeing coaches being upholstered in the old carriage shops in Swindon.

It was therefore comparatively easy to vary the bodywork as all it meant was that the window openings were cut out of the steel side sheets at different spacings so composites, brake seconds, brake firsts and brake composites were all possible.

With the change to monocoque construction in some Swindon designed and built intercity DMUs followed later by the Mark 2 coach it became more time consuming, in the days before computers, to manually restress the design for differing numbers of window openings and window and door spacings. (The monocoque had safety, weight and cost advantages over a coach with a separate underframe so it was a definite advance). Because of the design effort, the Mark 2 coach was built in a much smaller variety of body designs than the Mark 1 and the Mark 3, although the first design to benefit from computers to do the stressing, essentially only has one body style, that of an eight bay first class coach. The second class seat spacing was from the start always a compromise to get more seats in the same space as in the first class so the seats were always out of phase with the windows.


Up to the very last Mk2 variants they all had 8 seating bays with 8 corresponding windows in standard class coaches but only 7 in first class, also aligned with the seating bays.


To my way of thinking many of the perceived issues with window spacing could be avoided if the deadlights between the window openings could be reduced in length. This may require some more expensive strengthening of the sides between the windows to maintain the body's rigidity and crash-worthiness while keeping the natural bending and twisting frequencies in a suitable range. But I am sure it would be possible.

Since the 1980s full length bonded glazing with narrow pillars has been almost universal for road coaches. Of course road coaches are manufactured in a competitive market with buyers who also operate in a competitive market where the facilities and quality of the experience provided to their passengers is a very important selling point. Anyone who produced a road coach with window/seat spacing and alignment akin to many current rail designs would not be able to give the things away.

It is exactly the same as the reason modern train designs get away with being unpleasant spartan plastic tubes with nasty cheap seats, the least important criteria is the comfort of the people paying to use them.
 

hwl

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I appreciate your point about current production methods (of which I am aware), which are applicable to aluminium bodies made of extrusions, but I am not sure that it is such a show stopper as you imply. The Class 165 and 166 DMUs are also built using longitudinal double skinned aluminium extrusions (samples can be seen in the York railway museum) and have very small deadlights, see this image of a Class 166.

In spite of this existing example, engineering considerations were why I suggested that some more expensive strengthening of the sides between the windows may be necessary to reduce the length of the deadlights in future designs.

Reducing the length of the deadlights while maintaining body strength and keeping resonances within a suitable range is an engineering challenge. Finding a solution to meet current regulations will cost money and resources. Depending on the material used for the body, aluminium extrusions or steel (or even wound carbon fibre as now used for large aircraft fuselages and wings!) the design solutions will clearly differ.

Reducing the length of the deadlights with current aluminium construction techniques may be a non-starter, but this does not mean it is impossible in the future.

The simplest way to reduce deadlight width is reducing widow width (a per networker example above)
 
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