Not only is the video of the train that shares its tracks with a Thai market conclusively not a fake, as one suspicious reader suggested last week, but thanks to the diligent efforts of How the World Works readers, I have subsequently been made privy to an additional wealth of detail about this remarkable railway.
One reader, Justin Bur, even took it upon himself to place the train in the larger context of the history of rail transportation. I appreciated his e-mail enough to repost it here in full.
That train does not run on an ordinary main line railway. Although the line is owned and operated by the State Railway of Thailand, it is not connected to the rest of the rail system. At both ends (Bangkok's Thon Buri district in the east; Samut Songkhram [Mae Klong] in the west) and at the river crossing in the middle (Samut Sakhon [Mahachai]), the train runs through streets. The Bangkok end was cut back by about 2 km in 1961 because the street running was problematic in the increasingly heavy traffic.
These characteristics started reminding me of the electric interurban railways of the U.S. and Canada in the early to mid 20th century, and the vicinal railways of Belgium at the same time. It turns out that the Mae Klong railway was in fact electrified and used tram cars for the first 9 or so km out of Bangkok, between 1926 and 1955. Service is currently provided by diesel multiple unit cars -- essentially diesel-powered light-rail transit.
Then I came across a site called Tram Views of Asia which lists all the historical electric tramways -- mostly city streetcars, a few suburban/interurban lines -- of colonial twentieth-century Asia. Another site giving historical details of the Bangkok electric lines also mentions their foreign (European) construction and initial ownership.
This sort of light interurban railway was one of the most powerful engines behind the early (pre-WW2) suburban boom in North America. The Key System from the Transbay Terminal over the Bay Bridge and all over the East Bay was a prime example.
The interurbans mostly died out by the 1950s along with city streetcars; the Mae Klong line is a rare survival. But metropolitan light rail is on its way back in North America and Europe. Scenes analogous to the Thai market video (modulo cultural differences) can be seen in places like Strasbourg (France) or Ghent (Belgium) where trams and pedestrians share the street space in car-free city centers.
(Here's a Google maps link to the part of Bangkok where the Mae Klong line starts. The stations are shown on the map as blue dots. The satellite or hybrid view shows the right-of-way quite clearly.)
One last note: In my additional posting, I was remiss in failing to thank Christy and Elmore for initially bringing the video to my attention.