Remote Engine Control

[roydm]

I often see trains of 100 cars or more passing by my window, usually they have 2 or more engines in front but often they have an engine in the middle about 50 cars back or right at the rear.

What is the method of controlling the remote engines, it seems that a wire connection would be impossible.

If it's radio, how do they prevent a mix up when an engine gets taken from the train to use for another purpose.

Who is responsible for testing the link?

With a train so long I can't imagine radio would work well in situations like passing through a tunnel.

I'm ex railway but it wasn't an issue at the end of the steam era, they had a separate crew.

 

[crshears]

Hey roydm,

Look at this post

https://forums.radioreference.com/railroad-railfan-monitoring-forum/349209-locomotive-placement.html

Pay special notice to the long submission about half-way down.

You could also Google DPU [distributed Power Unit] locomotive.

CR

"As iron sharpens iron, so one person sharpens another." [Proverbs 27:17, NIV]

 

[roydm]

Thanks for that, very interesting.
Just one further question about the radios, how do they ensure the radio frequencies stay dedicated to a particular train i.e. what's to stop them moving the rear engine from Train A a different train B and the Train A engineer trying to still control the engine in train B?

How fast is the response for example if the engineer applies the emergency brakes what would be the time it takes for the remote engine to power down and apply the brakes as well?

 

[davidbeach]

There is a specific pairing process, it isn’t just frequency. If the radio is working as desired, an emergency braking application is immediately transmitted to the rear at the speed of light (radio) but if the radio isn’t connected at the moment the emergency brake application is a transmitted at the speed of sound through the pipe. The DPU will shut down and go into emergency when it sees that happening. Less than an emergency application won’t do that since the front end may be braking while the engineer still wants the rear end shoving with everything it has. Perhaps followed by the front end pulling in run 8 while the rear is still breaking. The rear can mirror the front or they can be controlled independently.