Thought you mught like to see these, they are pics of "Network Rail's" HST Measurement Train more commonly known to us as "The Flying Banana" but first a quote from Network rail as to what it does...
"New measurement train
The award-winning New Measurement Train (NMT) provides valuable information to our engineers on asset condition. The NMT is able to travel at up to 125mph allowing it to slot in between timetabled trains and is key to the delivery of the company’s objective to replace manual inspection with mechanised measurement.
The train, as well as producing video recordings of the infrastructure and the wheel/rail interface, provides six foot gauging data and information on track geometry. On board there is also a fully equipped conference facility for up to 12 delegates."
1) At Shottesbrooke on it's way from Plymouth to Paddington as 1Z19
2) Returning as 1Z21 from Paddington to it's home at Derby Etches Park
3) 1Z21 passes "Turbo" 165107 on an up stopper to Paddington