Life in Kolkata's (Calcutta's) suburbs is very much dependent on railways, In other words, Kolkata Suburbs is connect to Kolkata (Calcutta) mainly by these Local Trains. Similar to Mumbai local trains which are called "Lifeline of Mumbai", Kolkata (Calcutta) Local trains are heavily used/availed. People have their own group of "Train Friends". People play Cards, Discuss Cricket and football and even indulge in grave discussions on current affairs and also comment on "Anandabazaar ki bollo (what did Ananda Bazar Patrika say about a particular news)".
There is a particular name given to people who travel daily by these trains - "Daily Passenger" and traveling daily is known as "Daily Passengery", though the word "Passengery" is no where in the English dictionary :) .Few years back even I was a daily passenger. We used to remember the train timings by heart coz if you miss one train then you have to wait at least 20 minutes for the next train to come.
The trains are mainly electric trains, they are of two types "All Stop" trains that stop on all stations in that particular route and "Galloping" trains that stop on big stations only, just like "Slow" and "Fast" trains of Mumbai.There are four terminal stations in Kolkata (Calcutta).
Click on this link to see the railway stations marked in google maps with their names.
Kolkata (Calcutta) Sub-urban local train time-table can be found at following two links:
For Long distance trains you can refer to the PDF version of "Trains at a Glance" from this link
Also there is a nice PDF on Seat Maps or Seat Layouts of different Coaches, namely Sleeper, AC 3 Tier, AC 2 Tier, Garib Rath, Shatabdi etc., of Indian Railways available in this link http://erail.in/downloads/SeatLayout.htm. You can also click here to directly download the Seat Layout pdf file.
Another very useful website for knowing the exact train running information is http://www.trainenquiry.com/. This real time train tracking website is also available for smart phones, for details visit http://www.trainenquiry.com/mobile.aspx. In this website/application you can either enter the train name or number (it accepts even the local train numbers) and it will show the exact location where the train is. If there is a delay then that will also be mentioned. You can also search by station name and the website will show all the trains reaching or leaving that particular railway station. Say for example if I search for Barrackpore then it will show the trains waiting at or leaving from barrackpore station and the trains arriving at that station.