Loading refers to the electric power produced by the diesel engine/generator to make the traction motors go. Loading problems are usually electrical in nature and mean that there is little or no electrical power being produced to make the locomotive move. Bad contacts in the electrical system and problems with the generator are the two most common causes.
Lets talk about loading. When you here on the scanner that a loco will not load there is one problem, no power. The causes of this can be many, the battrey switch has not been turned on, the PC switch has tripped do to an electrical problem in the loco or the loco has been overloaded during operation. The PC switch must be reset before the loco will load again. There had been a relay tripped in the electrical cabnet which has tripped because of an overload and the relay must be reset. These are a few of the problems that will cause locos not to load. In the new locos (SD an GP 50's) and up, the problem of the loco loading can be in the on board computer. During long hot runs or long dymatic braking the computer my get to hot to work properly and crash. if that happends everything goes down. Until the comuter is reset nothing works. In the newer equipment to computer has it own cooling system, so it is kept below the heat level in the engine compartment in the loco so crashing is almost a thing of the past. Hope this helps. Shannon WP LIVES
Just to add a little to Shannon's list of bugs that cause no-loads... A ground relay, which is a short somewhere in the high voltage system. Sometimes can be reset, sometimes not. Cab signal, LSL or alerter penalty which will cut the power and apply the automatic brake. Trailing units may not load because of bad jumper cable connections from the leader. PC switch open which would normally be associated with some kind of penalty or emergency brake application. Traction motor failure. And as Shannon said...assorted electronic or computer problems, overheat conditions, overloads, control switch setups, etc. Just as an aside - the cooling system for the electronics is the a/c in the cab. It ain't for the crew, it's for the computers. If the a/c fails, it's fairly common for the display screens to shut down on hot days. Makes your life interesting when you suddenly can't see any speed, air or power incications. Makes me wonder what was wrong with round dials and strong-arm brake handles.
Alan, Your very welcome. In the US each locomotive that is produced comes with an enginemans manual. I collect these manuals along with trouble shooting and electrical manuals for different locos. So I have at my fingertips the how to's and why of not only electrical problems, but general trouble shooting of the loco. The other info that Rule 281 gave are more of the common problems incountered by trainmen and shop people. Hope this all helps, Shannon WP LIVES
