Amtrak's rhymes with:
backtracks, racetracks, soundtracks, backtracks, borax, mesothorax, metathorax, racetracks, soundtracks, wisecracks
Amtrak's sounds like:
amateurish, amateurs, ammeters, amtrack, amtrak, anadarko, anadarko's, anderegg, anders, andoras, andraki, andras, andrea's, andreas, andrej, andreozzi, andres, andreski, andress, andrew's, andrews, andrews', andrezak, andric, andrich, andrick, andries, andros, andrus, andrzej, andrzejewski, animators, another's, antar's, antares, anteaters, anthrax, antidrug