gunrunnerjohn posted:I suspect that "transistor" is probably a FET.
No, sadly not, these LC and LC+ boards still use a lot of BJT. You aren't wrong in your thinking though, a transistor that fails on is most likely a MOSFET, but that's not what they used.
Y1 happens to be the same 8050 transistor Lionel and MTH uses in a ton of accessories- just surface mount size VS TO92 through hole size.