The BTS (usually referred to as simply 'the sky-train') consists of two lines - the lengthy Sukhumwit line, which currently runs from On Nut to Morchit and the much shorter Silom Line, running from the National Stadium to Saphan Taksin. You'll see from the map above that Siam station is the only station where the two lines link. There is considerable construction underway to extend the two BTS lines in all directions but I'll get on to that later.
The MRT (usually referred to as 'the underground') is a single route from Hualampong to Khampaeng Phet. The underground 'connects' with the sky-train at two points - Sala Daeng (the Silom line) and Asok (the Sukhumwit line). Both interchanges require you to physically leave one station before entering another, in fact the walk from BTS Sala Daeng to MRT Silom is a good five minutes. You have the usual choice of single journey and stored-value tickets on both systems.
The BTS Sukhumwit Line
The BTS Sukhumwit line runs from the residential area of On Nut (lots of cheap apartments around here) to the bustling, predominantly Thai working-class area of Mo Chit (also the home of the northern bus terminal) During the morning rush hour thousands of commuters pour into On nut station, which serves the eastern side of the city, and you see many teachers traveling to Chidlom and Siam (possibly to connect with the Silom line) and also beyond Siam station to the many schools and universities in those areas. Riding from one end of the Sukhumwit line to the other would take in the region of 40 minutes I guess (I've never really timed it). Let's begin our journey at BTS On Nut, in the shadow of the giant Tesco Lotus superstore.
The BTS line travels from the terminus at On Nut to the grimy grey Phra Kanong area and then into the up-market residential neighborhoods of Ekkami and Thong Lo. After that it's BTS Prompong - a favorite stop for bejeweled socialites going to the Emporium department store and then BTS Asok for those wanting to transfer to the underground line. BTS Nana is slap bang in the middle of tourist territory and an exit point for those seeking hotels, pool halls, girly bars, pub restaurants and tailors shops. You get the picture. Ploenchit and Chidlom are both business and residential areas combined with dare I say it - a touch of elegance, and then it's all change for the Silom line at Siam (sometimes called Siam Central by those who just like to confuse people)
After Siam station - and pretty much for the rest of the Sukhumwit line - the vista completely changes. BTS Phya Thai, BTS Ari, BTS Saphan Kwai - gone are the flashy department stores, the apartment compounds and the five-star luxury hotels and their places are taken by characterless apartment blocks, office buildings with low occupancy and what might best be described as a sprawling mess. My apologies to people who live out that way because I'm sure Victory Monument does have its good points. I've just never found them that's all. It's not all bad though. You do get a nice whiff of chlorophyll as you alight at BTS Mo Chit thanks to its elevated position overlooking Chatuchak park.
The BTS plans to extend the eastern (On Nut) end of the line another five kilometres all the way to Samrong (hooray! that's near where I live) and work is set to be completed in February 2009. At the Mo Chit end of the line, an extra twelve kilometres is due for completion between 2010 and 2012.
The BTS Silom Line
The map above shows that the BTS Silom line is covered by just five stations, but work on extending the line over to the Thonburi side of the river should now be nearing completion (an extended distance of just over 2 kilometres). The Silom line begins at BTS National Stadium (something of a misnomer because the official national stadium is now the Rajamangala stadium in Hua Mark) and is your stop off for the mighty Mahboonkrong shopping center (MBK). After stopping at BTS Siam (all change for the Sukhumwit line) it then winds its way down to BTS Ratchadamri, with spectacular views over the Bangkok Royal Sports Club. BTS Sala Daeng is your stop for the top end of Silom Road and then it's on to one of Bangkok's major business districts, Sathorn Road, served by BTS Chong Nonsi. If you're a fan of concrete and steel constructions then you can really fill your boots around here. Then there's a quick look at the non-descript BTS Surasak, before the train pulls into BTS Saphan Taksin. With its riverside location, its nautical hustle and bustle and its impressive views, this is possibly my favorite station of all. Traveling from one end of the Silom line to the other takes about 15-20 minutes.
The MRT Line
The MRT or 'underground' is a single route from Hualampong (next to the main central railway station) right up to Kamphaeng Phet in northern Bangkok. I must confess that I've never ridden the whole line but it must take about 40 minutes at least. The MRT is a useful addition to the city's transport options but I personally only find it useful if I need the Petchburi, Rama 9, Huay Kwang area of the city, otherwise the BTS covers all my daily needs. I know quite a number of teachers who live in the areas around the Thailand Cultural Center (which you will see has its own MRT station) so the MRT is a godsend for those guys.
I always find traveling by underground far more pleasant than zipping around by sky-train. The carriages are far less crowded, there's a lot more space down there than there is above ground, and you are mercifully free from those annoying TVs and PA systems that are the scourge of the BTS.
If you use the MRT it's very important to work out your exit strategy. Because the MRT stations cover such vast areas, they typically have four exits. Failure to read the exit signs will have you emerging at street level like some half-crazed gopher, realizing that his destination objective is almost a pinprick on the horizon. I've been caught out many times.
The Teacher's Viewpoint
By presenting a few case scenarios, I think you'll get an idea of how much easier things have become for your average Bangkok teacher since the MRT and BTS started operations.
Tony has an apartment in Sukhumwit 56 which is about a five-minute walk from BTS On Nut on the Sukhumwit line. He's a corporate English teacher so most of the companies he teaches at are located near the sky-train line. He might typically have three classes a day - one at a company near BTS Siam, another near Sala Daeng (on the Silom line) and then his final class near Asok (back on the Sukhumwit line) Years ago, scheduling these classes would have been a nightmare. You might have spent ten minutes going from one job to the next......or it might have taken an hour during the rainy season. Your journey time was literally in the lap of the gods. Nowadays Tony knows exactly how long the journeys will take and can schedule classes accordingly, He can also move out to the On Nut area where there are some good apartment bargains to be had.
Greg works at an international school, located a stone's throw from BTS Mor Chit. However, he doesn't want to give up his lovely rented riverside house near to BTS Saphan Taksin. Years ago the thought of doing this kind of commute would be for mad fools and Englishmen, but thanks to a combination of the Silom and Sukhumwit lines, he's door-to-door in 50 minutes.
Fiona lives out in the Phahon Yothin area of the city but she's just a few minutes from the underground station. She takes the underground to Asok and connects with the BTS Sukhumwit line as far as Siam. Then it's all change for the Silom line and into the office on Silom Road. Even though her journey to work relies on her using all three mass transit lines - the journey never takes longer than an hour. Even the car-drivers using the expressway can't do it that fast!