Trolley Bypass System (as of August 2026)
In 2026 the HO scale trolley system was upgraded by using an Arduino Mega microprocessor and infrared sensors. Blue LEDs on the panel indicate where a sensor is covered. Each trolley has reflective foil attached under each end. The pulse width modulation of power to the track has helped during very slow approaches to the stops by avoiding stalls. The new system has four speed controls for each of the two bypass tracks plus a slow and fast adjustment. However, any adjustment is only effective on a reboot of the system. One master switch will start the trolleys if they are not at the bypass section of track. However, they will not stop until arrival at the bypass. The two trolleys will then begin automatic mode. The two signals at the bypass are directly wired to the turnout motors to show red if the turnout is not correct.
When using only one trolley, first find the toggle switch on the control panel that is marked up for one or down for two. There is a switch under the layout at the Thomasville Mountain to turn off the track power to enable easy placement of a trolley on the track. A single trolley will go straight through the bypass without stopping. An ampere meter above the control panel shows current going to the track. There is an LED panel light near the control panel at the rear aisle.
Circuit Description
The Arduino Mega code uses an array of eight stops labeled TW, GW, CE, RW, WW, RE,AB,GE where the first letter is the stop name and the second letter is the direction after the stop. Only the sensor at the next stop is read for a low indicating a trolley is there. Then any action such as a stop, timed wait, change in direction or wait for the other trolley is processed. Using the millis() function allows continous processing. Five L298N motor modules are connected to the track to control speed and direction. Another module is used to operate the two turnout motors simply by changing the polarity. One twelve volt DC. power supply rated at two amperes supplies the track and turnout power while another powers the Mega microprocessor. These have automatic shut down if there is a short circuit.
