The Viability of Solid-State Components for Signal Systems

This forum is dedicated to Riding Scale Railroading with propulsion using other than steam (Hydraulics, diesel engines, gas engines, electric motors, hybrid etc.)

Moderators: Harold_V, WJH

rkcarguy
Posts: 926
Joined: Tue Aug 22, 2017 10:33 am
Location: Wa State

Re: The Viability of Solid-State Components for Signal Systems

Post by rkcarguy » Tue Dec 12, 2017 5:17 pm

One thing I do envy about the aluminum rail guys, is one can easily hit it with carbide tipped wood tooling anywhere one wanted to add an isolation point. For the capture and release type system, I'm assuming it uses those timed relays I was looking at earlier for my signal system? In my search, some different ones came up that were activated by a momentary switch, with an adjustable time until it switched off from seconds to hours, or de-activated by yet another momentary switch. I could just see my coat getting hung up on that post and getting dragged off my train, so I'll pass on that type haha.
Like Chuck mentioned, you can have all the wiring and detectors you want, but without a dispatcher or logic(computer), there could still be jam ups because there is no way to "claim" a route of track otherwise unless it's wired to only be ran in one direction(with priority).
Because my track plan is simple enough(reversing loops on each end and a passing siding in the center) , it's going to be easy enough to set it up such that trains are "prioritized" into the center block main or siding via track detection and turnout position, and held until the opposite end of the RR is clear.

User avatar
ChuckHackett-844
Posts: 96
Joined: Wed May 03, 2017 3:54 pm
Location: Tampa, Florida

Re: The Viability of Solid-State Components for Signal Systems

Post by ChuckHackett-844 » Tue Dec 12, 2017 5:38 pm

rkcarguy wrote:I'm assuming it uses those timed relays I was looking at earlier for my signal system? In my search, some different ones came up that were activated by a momentary switch, with an adjustable time until it switched off from seconds to hours, or de-activated by yet another momentary switch.
The dead-simplest setup I have seen is a 'three-way' light switch at each end of the block wired as you would a hallway light switch. Each end of the block has a single red lamp. If the lamp is on, someone is in the block, if it's off the block is clear.

You observe the lamp off, you switch the switch to claim the block and observe that the light STAYED ON. If it went off immediately that means the guy at the other end switched his switch at the same time. Hopefully he noticed that the light did not stay on and waited. You switch it again and proceed only if it stays on.

Not without its problems, but dead simple. only three wires connecting the ends of the block. The lamps are wired in series to the center of the SPDT switch.
Regards,

Chuck Hackett, UP Northern 844, Mich-Cal Shay #2
"By the work, One knows the workman"

rkcarguy
Posts: 926
Joined: Tue Aug 22, 2017 10:33 am
Location: Wa State

Re: The Viability of Solid-State Components for Signal Systems

Post by rkcarguy » Tue Dec 12, 2017 5:50 pm

So I'll toss this out to the electronic goo-roo's, because I am not much of one.
Two trains are heading towards each other with several blocks between them, and have arrived to their last passing siding on both ends, with no passing sidings laying ahead between them. A typical system wouldn't let the other train know the other was there, until they both encountered yellow-then-red signals in the center of the route, requiring one train to back up so the other one would clear.
Enter a "master relay" system. Each end of the route would have a SPDT master relay. First one there trips their master relay(could be a "claim route" button or a piece of detected track), and it drops the normally closed leg which drops power to the other master relay at the opposing end, "locking it out" and setting all the signals red for that direction. The train that "won" the route, would either get all green's, or set its next block to green as it passed along driven by the detector circuits. I think it would work, but it would take ALOT of wire as one end is tied into the other and you've got relays on top of relays for the 3 aspect signal system.
Worst case, IF the trains hit it at the EXACT same time which would be super rare, you could end up with all red in both directions, but it would reset as the trains backed up out of the detection zone, or tried the "claim route" button again and one would "win" the route.
I realize that based on Chucks post, this could be just one long block, but lets say we want the prototypical experience of many signals on this route, therefore the issue.

User avatar
BigDumbDinosaur
Posts: 694
Joined: Tue Jun 28, 2011 9:19 pm
Location: Midwestern United States

Re: The Viability of Solid-State Components for Signal Systems

Post by BigDumbDinosaur » Wed Dec 13, 2017 1:17 am

ChuckHackett-844 wrote:So, on the turnout, diverging route to the siding, do you have a short section of detected track between the insulated joint at the signal and the turnout to detect that a train has passed the signal and thus drop the block to occupied? If not, does this mean that the train departing the siding is not detected until he reaches the other end of the switch?
If you mean a fouling blocks, yes those are present. If a wheelset enters one the nearest signal will change to STOP. There are no "leave siding" signals protecting the fouling points, except at the station exit, which is governed by an absolute signal and is fully interlocked with the mainline. We rely more on the engineers' having situational-awareness than on signaling to prevent conflicts. :shock: :wink:
Also: I looked on the ILS website but I couldn't find a track diagram. Is there one available?
I don't know if one exists in electronic form that can be posted on-line. When the ABS was laid out it was sketched on 18 × 24 quad-ruled paper (the stuff on which we did mechanical design back before CAD was invented) but never converted to electronic form.
————————————————————————————————
Science makes it known. Engineering makes it work.

Post Reply