All teams get an equal and very generous allowance for stock and other components from the series sponsors - including Hornby, Bachmann, Peco and Gaugemaster. One of the most stressful parts of the whole process is actually getting the orders done! It's a case of working out what you would like, then seeing what's in stock.
For our layout, we wanted steam engines and stock from around the 1930s or so. We cheated with a few items, but the overall effect was what we were looking for. Our stock list was as follows:
Adams Radial with 2 coaches - Lyme Regis pack from Hornby
MR 4F tender engine - Bachmann
Webb Coal Tank - Bachmann
2 x Class 59s - Hornby (Bodies removed and chassis and bogies used to support rocket platform)
Various flat wagons for rocket loads etc.
Breakdown crane - Hornby
2 x Guards Vans, Network Southeast - Bachmann
All stock received at least some weathering and quite a bit was fully re-painted by Phil. We wanted a slightly run down, care worn look, with the Martian dust softening and dulling the colours.
We didn't get time to run in the stock and the Webb coal tank in particular suffered because of this, needing the occasional prod to get it going. Everything else ran pretty well throughout.
We settled on DC control, simply to keep the amount of wiring and programming to a minimum. This is despite Matt having plenty of DCC experience and using it on his own layouts. When it comes to competitions, stick to what you know will work!