The other short form set which is easy to model is a test train. There are various ones but they are all similar in terms of relative shortness. It is even easier these days now that Modelzone has commissioned so many of the Railway Technical Centre (RTC) vehicles.
I have the wherewithal to model one of the test trains used when introducing what was then called the Intercity 225 trains. This was probably one of the last major testing programmes carried out under BR. The first vehicles to arrive were the class 91 locomotives and these ran firstly on test with a set of five mk3 sleepers in blue / grey corproate livery and a surrogate DVT formed of a class 43 power car with buffers, and then in service hauling mk3 sets with an HST power car as DVT. These latter trains went like the proverbial off a shovel as it was discovered that a class 43 didn’t like idling (just providing hotel power) for long without overheating so were instead wired to provide power too resulting in a train with 6,000hp.
(C) D Bower
Later on when the mk4 coaching stock was arriving, more tests were carried out and this included the formation I have the bits for. It consists of a class 91 hauling two mk4s, the mk3 Test Car 10, and a class 43, number 43051 on the rear. This was unusual in that it was a 43 which was not fitted with buffers which suggests that there was sufficient confidence in the 91 by then that failure wasn’t considered so much of an issue, and also that one of the surrogate DVTs wasn’t available (presumably because it was in revenue service on the back of a train of 91 and mk3s). This then is a 5 car set which was real, made up of ready to run products from Hornby, and therefore can run on limited space layouts without looking ridiculous.
Hornby R240 Clas 91
Hornby R452 Mk4 tourist open (x2)
Hornby R426 Mk3 RTC Test Car 10
Hornby dummy class 43 power car 43051 comes from Class 253 train pack R397, widely available from eBay and other second hand shops
Test train at the buffer stops at KGX. Image from http://www.traintesting.com