Why isn't a simple radar system used..vs the track circuit method.
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The radar signal could be interfered with by an object between the crossing and the approaching train. It is not fail-safe.
The track circuit is fail-safe in that anything that shunts the track, or otherwise interrupts the circuit, will activate the signals. Both the track circuit and the signals are operated by battery power, and are reliable for hours after any loss of commercial power (which is used to recharge the batteries).
I've heard that certain small locomotives and HiRail trucks are unable activate crossing signals. Why is that?
Originally Posted by Flash:
I've heard that certain small locomotives and HiRail trucks are unable activate crossing signals. Why is that?
Not heavy enough to make good, consistent contact between the two rails.
Originally Posted by Flash:
I've heard that certain small locomotives are unable activate crossing signals. Is this true?
Some work equipment motorized unit wheels are insulated,but any loco should activate the signals unless the track possibly hasn't been used for weeks or months such as on a branch line. Even then the signals will probably work. I guess I'm trying to say I haven't seen the signal not work in my railroading years.
