As far as I know they unload baggage in Kissimmee. We detrain in Kissimmee, one stop further than Orlando because its less congested, a ton of people get off in Orlando turning that station into a frenzy. Boarding there to return home is worse, I've been there once when a hurricane closed the route south of there and we couldn't board in Kissimmee and the people waiting to board coach was very very long and took 30-45 minutes to get them all on board, murder in the Florida sun, we had a roomette coming home and only 6 people boarded sleeper car. Kissimmee is closer to WDW, fare is 35-38 bucks to MK resorts and takes 20 minutes. Others claim that by the time the train gets to Kissimmee, people that got off in Orlando would be in WDW already. regardless, I'ld rather deal with 10 people detraining than 100 and everyone looking for baggage, rental, shuttle bus etc, just a small cab line at the Kissimmee depot and baggage for 10 people is fast and quick, we're out of that station in about 5 minutes.
Big problem for alot of people on the train is the lack of electricial outlets, like only one per car so take alot of batteries for hand held games and a spare battery for a DVD player. Watching out the window of a train is sheer magic compared to a car and a roomette that sleeps only 2, upper and lower, that my wife likes is the big window in the upper that she watches the lights, stars and towns go by while falling asleep. In the am, its breakfast and the pulling into Kissimmee around 11-12, train is always late, sometimes alot or a couple of hours. Some stops along the way take up extra time but sometimes its right on schedule. Pleasant way to see the countryside and day dream about life, and going home a good way to relax them weary bones from a hectic Disney vacation.