If locomotives slow down in the same location each time it might be due to a voltage drop due to wire length.
***Note, you must DOUBLE the length of your cable!!!
http://www.rapidtables.com/calc/wire/voltage-drop-calculator.htm
example 1 100 total feet of 14 AWG wire and 14V / 5amp system.
A typical HO layout 18% loss!
** Results may change with real wires: different resistivity of material and number of strands in wire
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