Platform exit signals

	most commonly: a PU (Danish PerronUdkørsel, platform exit) signal, which is on a signal mast and has a rectangular base plate with its top right corner cut off quasicircularly. The PU is special in that it normally shows white shunting signals but switches to coloured main signals in these circumstances: When an exit route past the signal is active When an active entry route ends at the signal When the signals functions as a cover signal for an active exit route Careful: some left track signals look disappointingly like PU's.
	less commonly: a regular exit signal with code U or SU which is a main signal. Normally it is combined with a dwarf signal if there are shunting routes leaving the platform point in the same direction.
	rare: TU signal, which has a strictly rectangular base plate. I don't think these can be found in more than one or two places. They are still here because I don't bother to remove them from the images. Their aspects are described under main signals.

When there are exit routes to multiple lines from a particular platform point, the signal there is has a code board beneath it showing a letter code for the line the active exit route goes out to - typically the initial letter of the next station along the line.