Great Western Coffee Shop

I went to Reading on the train from Twyford,
It was advertised a s "5 coaches" But the doors only opened on the Front 2 coaches. The rear train was dark and no-one was in it.

They would have been moving 2 trains together, but as there as no corrider connection on the 165s/166s and if its not busy it makes sense to only use 2 carriages

Speculation on my part, but if the rear three coaches were locked out of use, it may have been due to a fault in that particular unit.

Or if the unit had come from Oxford and had to stop at Culham or Appleford the rear unit would have to have been locked out of use, and reopened at Didcot Parkway.... if the driver remembered!

The internal systems (such as for signalling and the Train Running System (TRUST)) would need to be aware that the train consisted of five coaches, even if only two were available for passenger use. The public information screens would get their information from those internal systems, hence them showing the train as consisting of "5 coaches".

Hope that explains litecactus, and a very warm welcome to the Coffee Shop forum.  :)

I Remember that a train was cancelled earlier at Paddington because of a train fault.

It doesn't help that, even if the rear set is locked out of use, the yellow "Doors Open" lights still light up on that set when the train arrives at the station and the Driver releases the doors. This can cause confusion for passengers. It would have been better if 165/166's had been designed so that these lights don't come up on a set which is locked out of use (or even on doors which are locked out of use on a set which is in use). 

I suspect we could all think of quite a few things on 165/166's which could have been designed better .....

Not disagreeing with you, but the 'doors open' lights are not designed to be indications to passengers that the doors are open, although they do get used for that purpose.  They are indications for staff, and can also illuminate to indicate which carriage certain faults have developed in.

As IndustryInsider says, these yellow lights are used by staff. They're known as Cantrail Lights, and unofficially as BILs/DILs.

An illuminated Cantrail light could mean a loss of door interlock, a passcom activation, a fire alarm or a Track Circuit Actuator fault (there are other indications in the driving cab which help identify which is which).

When a door is locked out of use, next to the door both inside and outside of the carriage is an illuminated sign in red lettering saying that the door is out of use.

The train Was Standing Room only. Also on a Sunday Trains to Oxford are normally 5 coaches long.

Without knowing which train it's hard to speculate why the rear three carriages were locked out of use, though it's entirely possible just one set of doors had failed, which if it's the 'wrong' set of doors on a 165/6 can mean having to take the whole train out of use these days!  If there had been an earlier failure, then that set could also have been hooked on the back to get it back to the depot.

I accept that their purpose is other than to inform passengers that the doors can be opened, but that is how passengers perceive them, especially if they are used to travelling on the tube.  I've seen trains being delayed as passengers try in vain to open the doors on a locked out set, in fact I've done it myself before now.

The clue of course is where the Driver stops (if there are different stop boards for different train lengths).   If a 5 car comes in and stops by the 2 Car Board, then that's the clue that the back 3 are locked out of use.

Indeed that is a good clue, but only at certain stations.  If the station in question has a standard stop location for all trains, or the stop boards mean that it would not be clear of signals at the other end of the platform (such as at platforms 4/5 at Didcot) then there would be no way of telling.

This was platform 1 at Twyford, where the only stop board is a "HST Stop". The train went all the way to the end of the platform.

And, for the sake of pedantry and completeness, my trusty rule book module TW7 TW5 refers to them as "orange hazard lights" ;)

_{Edited because, as any fule no, TW7 refers to wrong-direction movements, not defective or isolated vehicles and on-train equipment...}

Welcome to the forum as well!, hopefully there aren't too many strange occurrences on your future travels :)

Not quite right.  There's an 'S' board (and associated mirror) at the end of the platforms where all Turbo trains (and 180s) will stop regardless of length - 6-cars being the longest accommodated, and there are 'HST 2+7' and 'HST 2+8' boards located just off the end of the platforms which a HST would stop at should it be in reverse formation.  A normally formed HST will stop with the power car just off the platform edge.

Agreed with Industryinsider on that one.