Train Falses

[AcuraTL]

Every time a train passes me I get a K band false. I live by railroad tracks so I have to stop to the RR crossings quite often.
I think it is something on the front and rear of the trains, since thats when I get the K false.

[Solidjake]

It's their communication system to their dispatch.

Try living in NYC with subways everywhere!!!!

[NLThor]

Could also be an AEI (automatic equipment identification) system, I believe they are used more on freight trains as a way to ID and locate specific cars...I think they work using radar

[goti]

I too have noticed the occasional K band false when passing a train. I have to be fairly close to it though.

[TRun]

radar speedometer for the train?

[Ray]

radar speedometer for the train?

Yes. I read somewhere (might have been on here) that trains use speedometers off the wheels and RADAR for wheel slippage. I guess it would be the difference between what the wheels "say" and what the RADAR is "saying".

[Rocketman59]

No, I work for the railroad. Loco's made by EMD (Electo Motive Division) manufactured since the mid 1980's have a K-Band radar unit mounted under the nose behind the plow ( Cow Catcher) It is used to control wheel slip by comparing the trains speed to the speed of each drive axle on the loco. If an axle is turning faster than the train is moving then the wheel is slipping and the electronics back off on the amount of current being sent to each traction motor until they match the trains speed over the ground. Since most freight trains have more than one engine, you would get multiple threats on your V-1. General Electric Locomotives have a different system and do not use radar.

Thanks

[Ray]

It's their communication system to their dispatch.

Try living in NYC with subways everywhere!!!!

I have heard of RADAR frequencies being used for satalite based communications but in the Ka band. I read on the net that some people use K band for communicating but it is a niche thing and line of sight, short range.

[supercowpowers]

No, I work for the railroad. Loco's made by EMD (Electo Motive Division) manufactured since the mid 1980's have a K-Band radar unit mounted under the nose behind the plow ( Cow Catcher) It is used to control wheel slip by comparing the trains speed to the speed of each drive axle on the loco. If an axle is turning faster than the train is moving then the wheel is slipping and the electronics back off on the amount of current being sent to each traction motor until they match the trains speed over the ground. Since most freight trains have more than one engine, you would get multiple threats on your V-1. General Electric Locomotives have a different system and do not use radar.

Thanks

Is there any other reason for the OP picking up a signal from the rear of the train? Some sort of system that tells the engineer when the back of the train is moving so he knows when there's no more slack in the couplers?

[bart99gt]

Close...

It is actually the wheel slip system used on some locomotives. It uses a low power K band transmitter to detect the speed of the train, then compares it to the speed of the driving wheels. If there is more than a pre-determined difference between the two the computer will automatically reduce power and/or apply sand to the slipping axle(s) to bring the wheels back under control. It is specific to a particular manufacturer of locomotives starting in the early to mid 80s on engines with DC traction motors. Locomotives with AC traction motors (the electric motors that drive the wheels) use a different system that doesn't require radar and is actually more accurate.

AEI is 915 MHz and railroad radios are in the 160 MHz range.