Just as an aside, what type of transformer are you running it with? There have long been complaints about the "jack rabbit" starts of these starter set K-Line types of engines. But they're always from folks using something like a ZW or any Lionel postwar transformer that starts with a minimal 6-7 volts to the track.
I've long said I think the Lionel 1033 is one of the very best transformers ever made for running a variety of non-command types of engines. The B-U setting of 0-11 volts is perfect for these sorts of engines: No rewiring necessary. I have the K-Line built version of your New Haven Alco and it runs slowly with no alterations. Are you then running a postwar or MPC engine next: Switch to the A-U setting for a more typical voltage to the track. There's a couple other what Lionel called "Multivolt" transformers, which have the possibility of lower starting voltage to the track.
I once had someone here suggest the 1033 is nothing more than a good door stop. Well sadly, he's passed on, but happily my 1033's are still going strong, as they always have.