But tractive effort is just a theoretical calculation of a loco's ability to get a train rolling . An 08 has more than a 67, but you wouldn't call that more powerful. And loco's will exert their maximum tractive effort without their throttles wide open.
Be very exciting to see just how well the P2 performs if they sort the issues with it's valve gear. The increased psi boiler for the A1 can already produce more steam that the cylinders need at speed, add a bigger grate, a cylinder diameter almost identical to a Duchess, plus it's Kylchap exhaust...it could well be a contender for the crown.
It will never happen but I would love to see the ECML opened up to race the big steam engines. A1, Duchess, 71000 and the P2. We all know the A4 holds the speed record, but few people would contest that given the same conditions that Mallard had, Coronation would have walked all over it. Incredible machines that really needed mechanical or oil firing to reach their full potential.