APT Formations

[northernrail]

Hi All,
Ive been looking at the APT a lot, its got me wodnering about how they were formed, i cant seem to figure it out, the Power coach in the centre moves in different pictures, and its normally two driving ends from different units?

 

[jopsuk]

the formations that were used in service consisted of two half-trains. These each consisted of
a driving trailer with genertaor for onboard power and passenger accomodation
four intermediate trailers
a guard's van trailer with passenger seating
(all those six were connected via shared bogies)
plus one (non driving) power car

these half trains were coupled at the power car end- so the full formation had two power cars in the centre. To solve the problem of two pantographs at high speed, the power cars had a 25kV line between them.

But for testing, shorter formations were used, often with a single power car. I believe the shortest possible trailer rake was a driving car plus a guard's van?
You'll find a lot to help you hereHowever, the test formations were often

 

[DXMachina]

The last time I ever saw an APT it was a power car, 2 intermediate trailers and two driving cars. 5 vehicles in all. Crawled through Apsley at about 60mph on the slow lines.

 

[Kali]

If you wanted to use a set in service, you attached a guards vehicle + DVT to the other end - the shortest combination of vehicles you could couple up - which explains the assymetric consists running around. For the sake of argument I'm calling a "set" a powercar + brake + trailers + DVT, if you want a full train you couple two of them together.

I'd quite like to know how complicated connecting intermediate vehicles was ( when shunting etc ), that's something I've not picked up yet. Mind you I'm a bit more interested in the -E train.

 

[sprinterguy]

The driving vehicles of the APT-P were not DVTs, as obviously they were passenger carriages. They were Driving Trailer Seconds (DTS).

However what you say is true, and I have seen several reports and recollections that on the later Glasgow - London relief runs that the sets worked in particular, but no doubt during other runs too, passengers were confined to a single half-set one side of the centrally located power cars, with the minimum number of vehicles, two, on the other side of the power cars simply to allow the train to be driven from both ends.

I too have been intrigued for some time about what the process was for splitting the intermediate trailer vehicles and how complex it was, as looking at photographs it looks as if the formation of the sets was altered quite regularly.

 

[Kali]

Yeah, my mistype, early morning brain issues...

Would have been sane to not articulate the driving vehicles really, then you could have just stuck one on the end of a set rather than split another set up.

 

[jopsuk]

The traintesting.com link I showed above shows a diagram of both the 2+12 formation of the "service" p-trains, and the propsed production version. This would have been similarish to the IC225 that was eventually produced. This would have had a Driving power car one end, a driving van the other (possibly still with an alternator set- it is marked as a "DAV") and three sets of three articulated carriages- one all 1st, one all Standard, and one with an "Unclassfied" restraunt, a catering car with standard class seating and a standard class car.
direct link- the numbers for each car appear to be the number of axles.

 

[AndyLandy]

Sorry for going off on a bit of a tangent, but how long are APT vehicles? I'd always assumed they were circa 23m, same as Mk3 vehicles, but if so, I can't imagine a 2+12 formation would fit in any platforms!

 

[sprinterguy]

Sorry for going off on a bit of a tangent, but how long are APT vehicles? I'd always assumed they were circa 23m, same as Mk3 vehicles, but if so, I can't imagine a 2+12 formation would fit in any platforms!

The driving cars are 21.44 metres long, the intermediate carriages are 21.2 metres long and the power cars are 20.4 metres.

And just to boggle your mind a little bit, when the electric APT programme was initiated in 1973, BR had plans for a "stretched" 2+14 version of the APT-P, too: I have no idea how they envisaged accommodating that in the platforms along the WCML, at a length of 338 metres!

 

[Kali]

Would the inner doors of the DTS fit? I have zero idea how long WCML platforms are. Otherwise I guess they lock the doors & make you hump your luggage... and it's not just platforms, signalling blocks in stations and so on too.

Sometime I need to calc the axle loads for fully loaded articulated trailers.