Advantages: 1) Fuel Efficiency. Ene

Advantages:

1) Fuel Efficiency. Energy use per rail ton-mile is only a small fraction of that per road ton-mile. This yields fuel savings and environmental benefits (less fuel burnt, less pollution).
2) Manpower efficiency. Instead of one man driving a 45-ton truck or a 50-seat bus, he can move a 10,000 ton or 700 seat train.
3) Land-use efficiency. A railway can shift many more people/hour than a road occupying the same land. All but the most car-friendly cities rely on commuter railways to shift their morning and evening rush-hour, and the ones that don't have to give over so much land for roadbuilding that they sprawl horribly.
4) Speed. Railway operators set their own speed limits, and thanks to modern signalling systems a train can go very fast while maintaining a higher level of safety than you would find on the road. 100-125mph is a reasonable maximum on traditional tracks, and on a modern dedicated high-speed route 180-200mph.
5) Safety: Railways are operated by highly-trained professionals both on-board and lineside, and controlled rigidly. Trains are separated by signals, and switches between tracks are locked by signals so collision risk is minimised.

Disadvantages
1) Cost. Building and running a railway is an extremely expensive hobby, and after you've built it you get to pay all your own operating and maintenance costs. That means it isn't worth building a railway unless there's a lot of traffic to be had.
2) Inconvenience. Unless you're a VERY good customer, it won't be practical to build a railway right to your factory gate or front. At both ends of the journey, you're probably going to have to use another mode of transport for the first and last few miles; car, taxi, bus or foot for passengers and delivery truck for freight.