New Jalpaiguri (NJP) near Siliguri is the nearest station on the main inter-city line. Direct trains to NJP run from Delhi (approx 27 hours) several times a day. If you are traveling from Kolkata (Sealdah Station)the best train for you will be Darjeeling Mail (circa 12 hours)running nightly at 10:05PM.
From there (NJP), the famous Darjeeling Himalayan Railway, known to all as the 'Toy Train' completes the journey to Darjeeling.
This route is very popular with tourists as it passes through some very picturesque mountain scenery and has been the subject of many romantic articles. The line has a series of zig zags and loops to gain height and runs straight up several village main streets! Trains depart NJP at 9 a.m. and arrive in Darjeeling at 3:30. Now the train is diesel hauled is reasonably reliable and punctual.
The steam 'Joy' train operates from Darjeeling to Ghoom round the famous Batasia Loop, once or twice a day (10AM)&(1:40PM) – enquire at Darjeeling station. Costs about Rps250(First class)/Rps 50(General Class)(CURRENTLY GENERAL CLASS NOT OFFERED (SEPT.2009)). Strongly suggested you buy tickets for earlier train as the 2nd train rarely has enough people.
A steam train also operates Siliguri to 'Agony Point' above Tindharia most Saturdays and Sundays. Enquire to Siliguri station. There is also a daily 'School Train' that leaves Kurseong at 06:15 arriving Darjeeling at 08:45. It leaves Darjeeling at 16:00 arriving Kurseong at 18:30. This is still hauled by a steam engine and is one of the last 'day to day'/ordinary steam trains running anywhere in the world. IR keeps changing the times for it and it is notoriously unreliable often running hours late.