Subway properties:

	_force-car-empty
		Attached to the subway program.  String value contains
		number of wizard program to force a car to be empty, by
		moving all its contents elsewhere.  If this is botched,
		the subway *will* crash.

	_disaster-room
		Attached to the subway program.  String value contains
		number of room to dump subway car contents in in case
		of internal failure in the subway system.  If this is
		botched, the subway may crash or it may dump the
		objects into #0.

	_subway-isa
		Attached to station platform.  Must be set on all
		station platforms.  Only presence is important.
		Indicates that the room is a subway station platform.

	_subway-train-name
		Attached to first station platform in a line.  String
		value is name to give to train car rooms.

	_subway-train-parent
		Attached to first station platform in a line.  String
		value contains number of room to parent train cars
		into.  Warning: everything in this room will be
		recycled every time the line in question is restarted.

	_subway-train-desc
		Attached to first station platform in a line.  String
		value is stored in the @desc of created subway cars.

	_subway-train-prop-<n>
		Attached to first station platform in a line.  <n> is a
		number, starting with 1; as many properties as are
		defined in a consecutive sequence are used.  Each
		property value must be a property name, a colon, and
		the desired property value, concatenated in that order.
		For example, to put a foo:12 property on the cars, you
		might @set here=subway-train-prop-1:foo:12 while in the
		station.

	_subway-start
		Attached to first station platform in a line.  Only
		presence is important.  Indicates that this platform is
		the first of a line.

	_subway-interval
		Attached to first station platform in a line.  String
		value contains interval in seconds between each train
		and the next.  If unset, or if set to a value less than
		10, causes the train generator to kill itself.

	_subway-stop
		Attached to first station platform in a line.
		Indicates that the line is shut down; no trains should
		be generated for it.  Causes the train generator to
		kill itself; before doing so it removes the property.

	_subway-head
		Attached to station platforms and subway cars.  String
		value contains dbref number of head of line.

	_subway-name
		Attached to station platforms.  String value contains
		the name of the station to be used in messages like
		"The train arrives at <foo> and its doors open.".  This
		string probably should contain the word "station".

	_subway-busy
		Attached to station platforms.  Used as a lock.
		Presence indicates a train is currently stopped at that
		platform.  Value is dbref of train room.

	_subway-station
		Attached to train car rooms.  Presence indicates the
		train is currently stopped at a platform.  Value is
		dbref of platform room.

	_subway-here-time
		Attached to station platform.  String value contains
		time to sit with doors open at that platform.  Minimum
		and default values are 10 seconds.

	_subway-end
		Attached to last station platform in a line.  Only
		presence is important.  Indicates that there is no next
		station.

	_subway-next
		Attached to station platform.  String value contains
		number of dbref for next station platform.

	_subway-travel-time
		Attached to station platform.  String value contains
		time in seconds between leaving this platform and
		arriving at next.  Minimum and default values are 15
		seconds.

	_subway-other
		Attached to station platform.  String value contains
		number of dbref for platform in other direction in the
		same station.  If not set, there is no "other" platform
		and nobody but this platform will see trains arrive
		here.

	_subway-daemon
		Attached to first station platform and to cars.
		Contains dbref number of daemon running the line (in
		the case of the first platform) or the car (in the case
		of a car).

	_subway-for
		Attached to daemons.  For line daemons, value contains
		the number of the head of the line; for car daemons, it
		contains the number of the car's dbref.

The exit from car trains to platforms is called

out;exit;leave;off;get off;get out;platform

changing this would require editing subway.muf.  The exit from the
platform to the cars can be anything as long as "train" rmatch picks it
up.  This exit will be relinked and locked and unlocked automatically;
its initial lock state and destination are ignored.