The Trans Eternal Railway, commonly known as The Train, is a transport device which connects Neighborhood 12358W to other locations in the afterlife. It is the only way in and out of a neighborhood and can only be summoned and operated by a Janet.
About[]
The train is first seen when it brings Trevor, Bad Janet and the rest of the Bad Place crew to Neighborhood 12358W. Soon afterwards, Shawn also arrives on a train, which Eleanor, Jason and Good Janet hijack to visit Mindy St. Claire in The Medium Place. During the succession of failed reboots, various combinations of Neighborhood 12358W residents use the train to visit Mindy again, though they have no memory of having done so previously. As the train is the only way in and out of a neighborhood, it was presumably the way that Michael and the demons arrived in Neighborhood 12358W in the first place, though this has not been confirmed. It is however strongly suggested by the fact that it is how the demons leave in Chapter 22. In that episode it is also seen that Derek, who is Janet's creation, is also capable of driving the train.
The locomotive pulling The Train has the appearance of an Earthly steam engine, specifically one used in North America in the late 1800s or early 1900s, but it's clear that it does not rely on any real physics to operate. The engine does not have a tender, and thus cannot carry fuel or water. Despite this, it appears to emit steam. It can also be easily operated by one person, unlike a real steam locomotive.
The actual locomotive prop is a full-size mockup, originally built for The Lone Ranger (2013). It is based on the dimensions of Illinois Central #382, a real steam locomotive built in 1898 by the Rogers Locomotive Works of New Jersey. #382 became famous after it crashed in May 1900, killing engineer Casey Jones. The full-size model was later used in the HBO series Westworld, as well as an Advil commercial.