(svn r5853) -Fix: [elrails] FS#178 Electric Trains can leave Conventional Depot
now the user will get an error if he tries to start the train and the status bar will say "no power" instead of "stopped"
Electric trains already driving in and out of non-electrified depots will still do so, but you can't start new ones

/* $Id */

KNOWN BUGS / PROBLEMS:

Normal and elrail depots look the same. Use 'X' (transparent buildings)
   to distinguish between them
Missing curors / icons for construction (currently using the conventional ones)