That BCDR 4.6.4T seriously looked like a monster, but as you say, the looks weren't matched by the performance, like the quare wan you met in a nightclub at 2 am when you were 19.........
Senior covered the whole BCDR at least once, and the main line and Bangor and possibly elsewhere) at least one more time. In all cases, I believe he travelled on footplates with a pass his father had signed. He used to say that the BCDR 4.6.4T ate coal at a voracious rate, though I'm not sure if he footplated it personally. He rated the BCDR 0.6.0s highly and had a sprightly run down the BCDR main line on the footplate of one with a fairly heavy load.