On my way out of the Yongsan Station to the Electromart, I happened to see the railway tracks and the train depot, which reminds me of Thomas the Tank Engine.
There you go, Thomas and his friends, and what I found interesting is that, if you try to search for Thomas in YouTube, you will be amazed at the numerous remixes there are, which includes remixes with, Eminem, Snoop Dogg and the others!
Up close of one of the railway signal. During the old days, where no electronic signals nor communication was the easily available, the Railway Master will pass some sort of a railtrack baton/switch to the train driver, which means that, only a single train can pass thru the railway track, and if another train wanted to pass/ use the railtrack, the driver will then hand over the baton/switch stick to the other driver via the Railway Master!
Also in the ol' days, in order to signal the other station, a signal was then passed thru the wire, thus the invention of the telegraf, and to switch the railtrack, a huge lever will then be operated in sequence, and if it was to be done not in sequence, then it will not work, and only now everything can be done electronically, via computer and real time tracking, thus eliminating or at least reducing human error.
Oh by the way, along the way on the street, I saw this "Thomas the Tank Engine" tricycle, for those who don't really know who Thomas was.