I know most of us use the Aristo Train Engineer or "TE" to control our large scale trains.  The TE has undergone many changes and improvements over the years.  One problem that has surfaced, but in many cases goes unnoticed, is a problem with output leakage current.   What this means is that there is often DC voltage on the track even when the TE has been set to zero speed.  In other words, the TE does not always turn off completely and lets a little current flow where there should be none. This is usually not noticed by the user because the load of the motor will usually drop the output voltage to zero. 
    In either linear or PWC mode, this problem can be annoying in that when you connect to a block with a train on it, you may see the loco jump from this stray voltage.  Other complaints that come up are from railroaders that use either Sierra or Phoenix sound systems.  Stray voltage on the rails will prevent these sound systems from functioning properly.  The voltage on the rails is usually just enough to prevent the special whistle signals for forward, reverse, stop, and blowdown from sounding. In addition, if your bell is voltage controlled, it might ring several times while the locomotive is standing still.  Very annoying, but something that can be corrected.
    To eliminate this problem, a bleeder resistor to the output of the TE will usually fix this problem.  You can go to Radio Shack and buy some 1K 1/2 Watt resistors which are relatively inexpensive.  Place the resistor leads on each side of the output terminals, and you should resolve your problem.