Yes, the station is still operating as normal. However, some of the long distance trains are expected to be moved to Bang Sue Grand Station in around September. Local and tourist trains are expected to remain for a few more years.
No, it is illegal to smoke at the railway stations and on the trains. However, they seem to turn a blind eye to people who smoke in-between carriages as long as it doesn't disturb other people. At railway stations, you may find an area set aside for smoking.
There are three terminal stations in Bangkok. At present, the main terminal station is at Bangkok Railway Station, otherwise known as Hua Lamphong. Bang Sue Grand will at some point start taking over as the main terminal for long distance trains. Thonburi Railway Station is the terminal station for some southern line trains and the branch line to Nam Tok.
(1) Special Express No.9/10: Bangkok > Chiang Mai > Bangkok
(2) Special Express No.23/24: Bangkok > Ubon Ratchathani > Bangkok
(3) Special Express No.25/26: Bangkok > Nong Khai > Bangkok
(4) Special Express No.31/32: Bangkok > Hat Yai > Bangkok
Odd numbered trains are ones out of Bangkok and even numbered ones are the return journey to Bangkok.
For more information and pictures, please click here.
The sale and consumption of alcohol is prohibited on trains and at railway stations. However, they do turn a blind eye if you are discreet. Even more so if you are drinking moderately behind the curtains on a sleeper train. The fine for being caught is 2,500 baht.
Sleeper trains are generally safe, particularly the newer ones. Doors are controlled from the inside and so you don't get people getting on and off like you do with ordinary trains. There are CCTV cameras throughout the train. The lights are also kept on all night. The sale and consumption of alcohol is prohibited. Although some people do sneak beer onboard, it is generally done discreetly and there is hardly any rowdiness. If you are on one of the Chinese CNR sleeper trains, you can actually book a berth on one of the carriages which are reserved exclusively for women and young children. If you are travelling 1st Class, you can book a cabin for yourself which obviously means you can lock the door from the inside.
You can book a berth on a sleeper train up to 30 days in advance. However, you may find that the newer trains on popular routes such as to Chiang Mai, will sell out fast. 1st Class usually sells out first as there is only one carriage with 12 cabins. If the new CNR sleepers are sold out for the dates you want, then check availability on the older trains. Most of the main routes have two sleeper trains per night.
You can buy tickets at any train station. You can call 1690 for information about availability and also to reserve your berth. But you would need to then go to the train station within 24 hours to pay for it. You cannot pay over the telephone. The State Railway of Thailand has an official online booking site called D-Ticket. You can also buy using online agents such as 12Go Thailand and Baolau. The advantage with agency sites is that you can book tickets more than 30 days in advance. Then, the second tickets go on sale, their agents will be in the queue to buy the ticket for you. You might not be able to choose which seat you want, but you will have a better chance of getting a ticket.
More information: How to Buy Train Tickets in Thailand