That's gonna need a damn strong alloy as the rail track, to be able to handle the forces put on it by that artillery.
Though I would say doing this regularly would be pretty bad (given that sparks are being made), the flanges of train wheels regularly rub against the rails in real life, especially along curves. So regular steel should do just fine. What I would be more concerned about is momentum displacing the track which is a real problem faced in real life caused by a multitude of reasons. While the track should be kept on the ties so long as the spikes are put in well, the ballast on well maintained track is compact but still in individual pieces meaning the ties and rails can be pushed through the ballast.
