SAFETY IS PRIORITY NUMBER ONE - All Aboard: The Complete North American Train Travel Guide - page 213

• The second engineer in the locomotive calls out passing sig-
nals to be certain they have been seen and noted by the engi-
neer. One of the two will relay that information to the con-
ductor by radio, and the conductor will acknowledge it.
• A train may not leave its point of origin without train orders,
which provide the engineer with the latest information about
track conditions and contain formal permission to depart.
Safety Equipment
Railroading is still very much a hands-on business, but more and
more automation is being introduced, particularly in the area of
safety devices. Again, it's impossible to list all of these gadgets,
but a good sampling should give you the idea.
• As mentioned elsewhere, in every locomotive cab there's
something called an alerter , which is designed to make sure
the engineer is always in command of the train. If the engi-
neer doesn't change the throttle position, touch the brakes, or
blow the whistle (on some locomotives a special button must
be pushed) for 20-25 seconds, a strobe light will begin to
flash in the cab and a loud horn will sound. At that point the
engineer has just a few seconds to perform one of those tasks
(as if to say, “Yes, I'm still here and still in control”). If he or
she doesn't, the brakes will be applied automatically and the
train will come to a stop.
• Located beside the tracks are electronic detectors that broad-
cast warnings to the train crew if the detectors sense over-
heated journal bearings (called hot boxes) or any kind of
dragging gear. For more information about these devices, see
chapter 10, “How It All Works.”