* UPDATE: A drawing illustrating the use of a "transparent" shunt dwarf signal is included in the file package *
Shunt signals (violet / yellow) must be obeyed by shunting moves, whereas scheduled trains can neglect them. (This is entirely different from the French system, for instance, where all moving consists must obey shunt signals.) In Trainz, however, stop is stop for every train. This must be taken into account when programming AI schedules. Some of the shunt signals in this set will show yellow on a CAUTION state (i.e. the next signal is at stop); this partly eliminates the problem.
The real "SHUNT" state (shunt allowed) also has a yellow aspect, but it must be attained through a SHUNT modifier on the track, and this will be undesirable on main track in general. Another way to obtain the SHUNT state requires the use of a modified version of the scripted asset "Set Signal Ahead"; it exists but cannot yet be supplied here awaiting the approval of the author (elstoko).
Shunt dwarf signals are especially used on "wrong track" (contre-voie), i.e. on a through line against the main running direction, right before a junction leading to the yard or to station tracks. They are commonly placed at the right-hand side of the track. This is what the 'transparent' shunt dwarfs in this pack are for. The transparent dwarfs themselves react to SHUNT modifiers on non-occupied tracks, but they are transparent to the search for feathers and modifiers starting from other signals that precede them on the main track. In this way, a main line branching signal can react to feathers on a junction beyond the shunt dwarf signal. This transparency of the shunt dwarf is only useful if it has both a SHUNT and a CAUTION state, for otherwise it will not open for the main line train finding its way through a diversion to a station track.
On tracks where every moving consist has shunt status, shunt dwarfs may be found as a replacement for stop dwarf signals.
Dwarf signals (or: ground signals) are used mostly on spurs and sidings of lesser importance, and on yard tracks.
Stop dwarf signals (a rectangular board and red/yellow lights) are situated on each track of a yard throat even when a common departure signal is used for all the tracks. In the prototype, one of the dwarfs will open when the common signal is cleared. (To simulate that behaviour in Trainz, place a REPEAT-NEXT modifier between the two signals.)
A stop dwarf may be found playing the role of a shunt dwarf signal in shunting areas.
The pack also contains a similar signal on a post. Its use differs from that of the dwarf signal: it is commonly found on spurs and very minor branch lines, just before the junction with the main line. Its yellow aspect indicates that the train or shunting consist must continue with caution until the subsequent stop signal is reached. Only one post height is supplied, though the height varies in reality.