If you have 2006 the HST it is already there. Go to the train icon in Surveyor,then click the loco button and scroll down to the HST. The train is exactly like the original HST except for an independant brake handle on the console which was not on the locos. Other than that,it can be driven same as the real ones. By the way.I carried out the original speed trial between York and Darlington when it broke the speed record for a diesel, at 145 MPH.
Harry Failem