Consolidated Leo posted:stan2004 posted:Agreed going the other direction up hill would apply full track power, but wouldn't the train eventually trip the top-of-hill sensor and lock in the track lower voltage until the train makes a complete loop and trips the bottom-of-hill sensor?
You are correct. This condition, although unplanned and annoying, does not matter. Since there will be no train on the grade when this occurs...
Not sure we're talking apples-apples. If the train is backing up the hill, say the caboose trips the top-of-hill sensor. The way your relays are configured, the top-of-hill sensor always takes precedence (if both sensors are tripped simultaneously). So the voltage would drop on the grade and the engine might get starved of voltage and perhaps even stall! Likewise, you might have a MU consist or even a pusher engine configuration. In such cases, as soon as the lead engine reaches the top-of-hill, any helper engines that are still on the up-hill (or that have not even started their ascent, might be starved of voltage.
I realize this is all just yakkity-yak... 
