Calgary's and edmonton's (and similar types of LRTs) have the bad design where the pairs of cars couple together & there is a gap between the cars:

from:
http://www.ottawa.ca/residents/public_consult/tmp/lrt
Its easy to fall in between the cars and there won't be an alarm to the driver that the doors aren't closed & locked. Someone with limited vision can easily mistake the gap for a door & fall off the platform thinking they were stepping into a LRT car. If the fall was serious enough, they could be dazed or unconscious from the fall & be unable to save themselves from the train rolling over them.
Notice further down the train are the accordion folds where the three segments of the car bend to get around curves, and this accordion fold runs from the top edge of the car to the platform edge making it difficult to accidentally (or otherwise) get between the car & the platform.
The Skytrain Mk I and Mk II cars have the same flawed design - there is a gap between the cars where they couple together, but where these cars have their permanent connection between married pairs, there is also a gap large enough to fall between. Fortunately, there are alarms at the platforms to alert the computers of a person on the tracks, but if the train is moving when the alarm is tripped, it can still travel for some distance after the emergency braking system is activated.
NYC had a no-tech way of filling in the gap between cars:

from:
http://www.thejoekorner.com/
Ugly, but it worked.
Although it would have worked better if the diamond hashes ran from the platform edge to shoulder-height or head-height.