Stop Circuit For Crossing

Shown here,whichever one gets there first will have the right of way

 

www.jcstudiosinc.com/BlogShowT...=434&categoryId=

 

Can also be done where the train has priority and does not stop,a bit more complicated

 

Dale H

Dale I looked at your diagram earlier and I really appreciate you help and reply.  What I really want is a schematic where the train has the ROW and the streetcar  stops.  I'll also install a crossing gate on each side but that's not a problem.  Any additional help you can give will be much appreciated.  Thanks again.

The schematic is actually more simple. When the train is in the approaching block of the crossover,it cuts power to the trolley line stop block in the approach but not right in the crossover center where the train can hit it..  If the trolley is already too far in the block and in the intersection itself,it proceeds and beats the train. So the middle block of the trolley line is always hot but the approach to it is cut off. The insulated center rail for the trolley has to be carefully placed. To do this the train insulated outside rail has to be a little longer on the approach giving the trolley ample time to beat the train if it is already in the intersection. If the crossing gates actually impede the trolley you would have to use a time delay module and relay separate for the gates giving time for the trolley to clear before the gates come down. A few seconds should be enough. See Mars timer circuits on my blog for delayed action of a circuit.

 

This will work if the trolley does not stall for some reason (such as a dirty roller)  in the crossover and also assumes unidirectional operation. Bi directional is more complicated but can still be done.

 

So I would say you are looking at a relay for the stop circuit DPDT and a relay for the gate and a timer if the gates impede the trolley. If the gates do not impede,or if the gate is placed in front of the hot section of the crossover then 1, 3pdt relay should do it all.

 

Relay(s) are activated by the outside insulated rail method shown in my blog also.

 

Dale H

I'm sure that Dale has it on his more complicated schematic; but you need a failsafe to protect the trolley. If it has already started across, then the train n must wait.

Bob

 

If the train is already in the crossing,the trolley approach block will be dead. When the trolley arrives it will stop until the train leaves.

 

If the trolley is already in the approach block and the train arrives,the trolley will still stop unless it is too far in the middle. If one roller is in the hot middle section,it will continue running through the block and out the other side. Since the insulated rail for the train is far enough away,the trolley should have ample time to get through the crossing before the train arrives.

 

Only an outside insulated rail is needed on the train approach. For unidirectional operation perhaps 4 feet on the approach and 6 inches on the other side of the crossing. Only an isolated center rail section is needed on the trolley approach. Perhaps 12 inches in the approach up to a hot center in the middle. A 3pdt relay is needed. One contact set NC removes power from the center rail of the trolley approach block. A second contact set works the gates (assuming the gate does not impede as described). An optional 3rd set can work a block signal for the train..

 

Again this takes some thoughtful placement of the 2 isolated blocks.

 

If really worried about a collision I guess an additional safeguard with an additional relay could be used making a safety shutoff.. Make an outside insulated rail in the trolley line right in the intersection activating a relay and shut off a small section of the approaching center rail of the train much closer to the center. If everything was normal the train would not be affected. If the trolley stalled or did not clear in time the train would run on the approach but shut off before it hit .. However I think it would be reliable without it..All this is harder to describe and draw than actually do.

 

Dale H

Thanks a ton Dale.  That's exactly what I was looking for.  You're a lifesaver.  Take care.....I have another question for later.

Hi Nick

 

After thinking about it,Bob is right. I would use 2 relays to be safe. The gate could be wired through the second set (on the trolley line) one set to make sure it does not come down on top of the trolley,then no timer would be needed,the other set as a safety shutoff for the train if the trolley does not clear. The gate is what bothered me the most. Better to have positioning logic on both tracks. So I think all that is needed is 2 relays to have a good circuit.

 

It is hard to draw all the wiring on a crossover and have it show well on the web as it gets busy and looks messy. If you are stuck I can hand draw you a sketch and snail mail it. To be honest it is easier to actually wire up 2 relays than draw the darn thing. 

 

Dale H

Dale,

If the train relay would operate through a normally closed contact of the trolley relay; wouldn't that do it? The dead zone for the trolley would have to be ahead of the operating zone of the trolley relay.  You would also need to measure the coasting capabilty of the equipment in use. Would you use any protection to keep these relays from sticking up?

Bob

 

Yes,the NC contacts of the trolley relay could be a fail safe shutoff if the train is too close. Most all trolleys stop pretty fast as they have worm gears but if it shut off,then coasted into the center portion it would touch the hot section and resume going through the crossing. Remember ,we are giving ample length on the train approach to allow the trolley to get through so it should not be an issue. Either it will hopefully stop in time or proceed through before the train gets there.Coasting of the train would have to be considered with long enough insulated center rails. Roller jumping can be addressed in a couple of ways,with relay contacts if need be. However in this application it would only be used if the trolley stalled in the middle as a safety.  I was trying to keep the circuit as simple as possible. You can also alter the trolley a bit to leave the lights on when it stops,but that is opening another can of worms.

 

The relays I use never "stick" or at least it has not happened to me.. They are spring loaded,industrial quality with at least 10 amp contacts.With a capacitor across the DC coil,chattering is not an issue,they work very smooth. I have never experienced failure of any kind and they should outlast me. A bigger problem is keeping the rails clean so the equipment runs right and spacing the insulated rails.

 

Dale H

I too am thinking of doing a similar project and have some thoughts to consider.
I think the size of the layout and the length of the train, number of trains running on this loop if a large layout, need to be considered as well as what else is running on the superstreets. If only one trolley then the solution by dale is an excellect one, but if more than one trolley or other superstreets vehicles are running, they can easily pile up at the crossing causing derailments etc. Would it be easier in that case to plan a circuit which just shuts down the power to superstreets and everything on superstreets stops for the time needed for the train to pass. Question for Dale:What would you use to do that - relays?. In my plan there are actually four crossings - two in one direction and two for the return trolley route, with three trolleys and two superstreets vehicles - approx 75 feet of superstreets in loop and two or three trains on railroad loop. A bit more complicated. I think it best to shut down superstreets loop when train approaches crossings.
Larry S

Hey guys I really appreciate the time you took to explain everything.  I looked at the Dallee modules and have decided to use the relays as suggested.  I'd much rather unplug and replace a relay rather than a whole module.  I'm going to be using plug-in relays throught out the layout.  All my wiring will go to terminal strips then to the relay sockets.  Much easier to troubleshoot if something goes wrong.  Thanks again for all the help.  BTW I'm buying all commercial grade components from Allied Electronics.

Assuming you can put in an insulated rail in the super streets,a regular block system with relays would work. Either point to point where one trolley starts the one ahead of it or an actual block system where the trolley behind is stopped. The crossover stop is a separate circuit not really related to the block system.

 

Point to point for 2 or more trains (or trolleys) is described here. Only one train runs at a time,a blessing with competing sound systems on trains.

 

http://www.jcstudiosinc.com/BlogShowThread?id=612&categoryId=

 

Nick

 

Good relays with sockets can be had for $8 each.

 

Dale H

Everything Dale said above is on the money, I send alot of people to his web site for tips.

I just wonted to add that I too found that relays and terminal strips makes life alot simpler in a number of ways. I use them on many applications.

 

What I would suggest though is a fuse on the AC side of the bridge rectifiers that drive the DC relays. A 1/2 amp should be more then enough. I know it's a little over the top, but I always say, "better safe then sorry".