Millennium Line - Evergreen Extension | Completed

[aberdeen5698]

Originally Posted by jsbertram

Since the LIM requires electricity to generate the magnetic fields to move the train, when there is no LIM power there would therefore be no magnetism in the LIM for propulsion, nor for LIM braking.

It is possible for the LIM motor to brake the train using no external power - see this paper, which states:

Since the generated electric power can be allotted to the armature copper loss, an on-board energy source becomes unnecessary to maintain excitation of the LIM.

The issue would whether or not the vehicle control systems could maintain excitation of the LIM coils during the transition from powered to unpowered mode.

Originally Posted by jsbertram

Loss of power should cause the train to go into Emergency Braking...

I think we all understand that the system uses conventional wheel-based braking for emergencies and when stationary. The issue being discussed was the advantage of LIM braking on steep grades in inclement conditions because it doesn't rely on wheel adhesion, and whether or not that advantage was negated by the need to maintain separations based on worst-case scenarios (i.e., power loss).