The Home Machinist!

Does someone have a detailed description (and schematic if available) of the implementation of "Trip Track" block signals supporting Red & Green?

This approach does not directly detect trains in a block but uses short pieces of track in place of the capture/release buttons used on some railroads.

I have heard of implementations that use one short length of track at each entry (capture) and another at each exit (release) but I have also heard of implementations that use two short sections at each entry & exit.

I am most interested in exactly what happens when things don't go as expected, i.e.: a train starts to enter or exit and then reverses direction, etc.

Regards,

Chuck Hackett

The only trip track I've run across was years ago at Harry Herder's. There was a tunnel with a short curve immediately ahead of the entrance. Harry installed a switch to detect trains entering the tunnel and trains exiting. The idea being the signal would display stop when a train entered and clear when it exited. He used mechanical switches that presented it's own issues.

Common with tracks using the capture/release system two trains running close together would often run two sections. This left the second train in the tunnel with a clear signal behind it. Between this and issues using mechanical switches he abandoned the signal.

I think the largest concern is simple space and length of the track layout. Real trains keep blocks of track between each other, so that if a train were stopped in the tunnel, the signal would show a red aspect, the one for the block prior to that a yellow aspect. If the train in the tunnel started backing up and the train following it was still blasting along despite the yellow aspect telling it to slow down and prepare to stop, they could still have a collision if the train backing up went backwards into the prior block that *was* indicated yellow and couldn't be seen, around a blind curve for instance. If this was the case, I would say the blocking is incorrect, and that the curve should be included in the same block as the tunnel. I.E., there always needs to be enough room to visually see the next signal, and be able to stop before passing it, instead of coming around a blind corner to a signal(or a caboose backing up towards you!). So lets say you had a blind curve coming up to a tunnel, and when your 7-1/2" gage train is fully loaded it takes 30' to stop, I'd think you'd want to have the signal and block located 60' before the start of the blind corner, and in open view of any following trains.
This is why signals can't solely manage the trains for you in my opinion, "road rules" as well as radio's in case of emergency need to be part of any multi-train operating system.

In the case of Herder's signal the balance of the track was run elephant style, everyone running the same directions keeping an eye out for the train in front of them. This carries into the practice of running two or three sections through the signaled block. It's a practice I've seen on pretty much every bi-directional track I've run on. We're all used to running un-signaled track. If there are two or three trains waiting the engineers will agree to go through as a group. The first train captures the block and the last train releases it.

With a trip track you are bring in an automated element. The signal system will capture and release the block for you. To be successful it would have to be run in a prototypical fashion. One train at a time, engineers who understand and adhere to signal indications.

Chuck, My understanding is the prototype actually uses trip tracks to take single track in between Augusta and Greenwood. As far as the model application goes there is a benefit where you could have it seal in logically or hardwaired based on the requesting direction, that it it makes a really easy way to tumbledown the multiple segment block. I played this idea on paper once and realized its application is easy and the reset is easy (clear the single block and it goes to green) the only limitation was you have to get both seals back to a same logic point. That is the processor, hardwiring, what ever has to know both the east bound seal and west bound seal to evaluate who gets what.

ANyways, never made it off the paper...

JP

Street car lines used a device on the trolley wire that detected a trolley wheel passing. The system counted cars in and out between these installations. A car backing thru a detector it had just cleared caused a bad wreck on TMER&L since the device only worked in one direction.
Track occupancy is a better plan but use plastic ties. I used wood and they got wet and passed enough electricity to keep relays engaged after the train cleared the block.