The best thing to do is go to your RRB office and ask (take along a list of all your concerns and questions, even ones you might think silly) because it's really complex and their publications aren't paragons of easily comprehensible English. If the rep you get isn't very helpful, ask for another one -- you'll probably have to make an appointment by calling that 800 number.

The only other thing I can recommend is to retire at the beginning of a month, right after you've made enough trips to pay for the medical, rather than at the end of the month. This is because the medical contributions you make this month pay for coverage through the end of following month (vacation pay in the month also figures in). The reason I say this is because I know someone who retired on the first of the month, and HR reported things to the early retirement program incorrectly by one day (the vacation pay counted for that month, but HR overlooked that). So the Plan was trying to short change him by a month (took about 6 weeks to get it straightened out). These medical benefits aren't part of the RRB, BTW.