Model Railroading — Blog Post #3
My first layout, the 4’x8′ setup with a simple oval of track, had been taken apart. I was using the plywood table for the base of my Marklin layout which was in my bedroom. I now had three nested ovals of track with turnouts connecting them. Marklin made sectional track and the curved sections came in three different radii so I had one oval for each radius of curved track. I setup signals on each oval and contact tracks to control the trains. For each oval, as the train went past the signal as it left the station, it would trigger the signal to turn red. The train ran around the oval and as it approached the same signal now showing red, it would trigger the signal on the next oval to turn green. The first train stopped at the red signal and the second train started up on its oval and as it came around it would trigger the signal on the third oval.
For all this to work, I had to start by setting the signals on all three ovals to red and position each train at the respective signal. With the power on, I would change one signal to green which allowed that train to start up which started the whole process. At the time I had no way of knowing that I was dealing with control theory. Having all the signals at red before I started any of the trains was a set of initial conditions. The process of one train running, triggering the next train to start and stop only worked if all trains were stopped initially. If I had let more than one train start running, I would have a race condition as to which train got around the oval first, which train stopped and started another train and so on. I wouldn’t see the theory of all this until graduate school.
This layout, with three ovals of track and signals that automatically controlled the trains was my favorite for a long time. I would build other layouts, of course, but I always remember how much I enjoyed the signals controlling the trains. It was fun to watch the colored lights of the signals changing and the trains starting and stopping on their own. I had recreated what I had seen at Berkeley Hardware. It was fun.
I wanted to have a larger layout and this meant a move to the garage. I added a second 4’x8′ sheet of plywood to the existing one and formed an L-shaped layout. I wanted to have several different levels of track on this layout so I built a series of piers out of wood to support the elevated tracks. It was primitive and clearly I had not learned about the L-girder approach. It did work, after a fashion, and I was able to run trains along the different levels. I also added metal screen and plaster to form the shape of the ground and then covered that with grass sheets. Overall I was happy with the look.