HST▸ 's were banned from entering Penzance Train Shed because of a cock up when the roof was replaced about 20 years ago, due to the "Vortex" design in the roof being sealed on 1 side.
This meant the "Vortex" NO longer worked.
Ok so all FGW▸ HST's have new engines that produce less exhaust gases, BUT either HST's CAN OR CAN NOT enter the Penzance Train shed, so they should STILL be outside the Train Shed OR now enter the Train Shed and pull up at the buffers.
Well they are allowed in as little as possible to get rear p/c on the platform.