It's a very odd locomotive, turns out it's a a re-engineered locomotive, rebuilt by Brush Traction, Loughborough from redundant Class 47 locomotives. For TSW i'd be quite unique engine because it shows a transition from old to the same old but with new things and new abilities The locomotives are fitted with a refurbished EMD engine and a re-conditioned alternator, improving reliability and performance. Here is the GWR livery. This locomotive was given a variety of nicknames such as Thunderbirds Bodysnatchers or Zombies due to the fact that it's a re-engineered variant of the original class 47.
Almost. The "standard" and HST versions of the Mk3 have a few differences between them. HST version has no buffers for example. So there'd be a few adjustments needing to be made.