Quick and dirty 10car 455/456 with gangways within unit is split the 456 and put the 8car 455 between the two 456 cars, with only a relatively simple coupler mod to one car at each end (i.e. leave the 455 tightlock and replace the 456 bar, or do v.v.).
That is a simple way to get 10car trains of this stock running, but SWT don't need them that urgently.
However, I do recognise that gives a semi-permanent 10car train that can't be split in traffic for practical purposes - even between the two 455s. One 456 car is a motor and the other a trailer, and while each 5car bit would work, one is over powered the other under powered, and then there is the risk after detaching, running split, when they next go to attach you might get two under power units meeting. Or two over powered units meeting. Or two units meet 456 end to 456 end, etc, etc ,etc.
Before anyone takes the above too seriously, it is partly in jest, but partly to demonstrate you could run 10car trains of this stock and meet all the intra train gangway needs.
Further :
I can't see that converting a 456 cab end to a through gangway is that extensive, it is the same cab end structure as a 319, indeed 319 / 321 / 456 are all off the same production line. The structure does have enough space for a gangway ... I'm not saying the current 319 end layout is suitable for anything but emergency use while stationary, but none the less the aperture is already there, and thats the biggest thing to make. Cost effective ? Doubtful.
Second, I had never heard the 455/456/455 suggestion before this thread. Where did that come from ?
Now this is actually how I would do it ... form 6car 455s by putting a single 455 between the 456 cars, and run 4+6. This keep motor:trailer ratio balanced. It does mean you can't get through a 10car, but I can't see any real operational reason why that can't be done, and I don't count an RPI can't get through as operational. All they have to do is ensure detttach and atttach diagrams don't have two 6cars meeting.
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Nick
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