Looking for 2 train solution ?

[dbaker48]

One application I have is for a 2 train operation on a simple oval, with a passing siding.  I would like 1 train to go "north" around the oval, clear the siding and stop, then a 2nd train leave the siding heading "south" and travel the oval, return to the same siding and stop.  Activitating the 1st train to go "north" again.  Of course continuous operation.   Any ideas.

Using non-derailing switches, cross wired so they activate each other
E units will be set in forward direction only. 
Trains will be Polar Express, and probably "General" from MPC  (AC - DC motor issue?)
Siding will be long enough to ensure adequate "clearance" for both trains.
Convential Mode Operation (ZW xfmr, old one)
Track - probably O scale lionel
Switches - 022

Thanks

[ChiefEagles]

Bob Nelson can do it [he has it that way at his house]. 

[lionelsoni]

Frank, the loop above my layout that you're thinking about is quite a bit simpler than what he wants to do.  But here is how I would do it:

You will need 5 DPDT relays. It doesn't matter whether AC or DC, as long as you have a suitable power supply for them.

Each siding has two control rails, one at each end, and a stop section with an isolated center rail at the end where the locomotive will stop. The control rail at that end is arranged so that it is bridged before the locomotive stops. The control rail at the other, entrance, end is cleared by the end of the train and not bridged when the train stops.

There are two relays for each siding. The first is an "arming" relay which is operated by the control rail when the train enters the siding. It has a latching contact, which bypasses the control rail to ground when the relay operates. The other contact on the arming relay is in series between the "power" relay's coil and the other control rail. So, if the arming relay is latched by the time the locomotive reaches the end of the siding, the power relay will operate, even though the train is past the first control rail. The power relay controls track power to the stop section of the next train to run. It also has a latching contact that takes over from the control rail when the relay operates.

The other ends of all four relay coils are connected to the appropriate supply voltage, except that the arming relays' coils are connected through a normally closed contact on a fifth "reset" relay. The reset relay is operated by a control rail somewhere in the section of main line that all the trains pass through.

The two switches for each siding are of the non-derailing type, with the coils within the pair connected together, so that when one switch throws automatically, the other matches it. This way, the switches are always lined to return the train whence it came.

Here is the scenario. A train leaves its siding. As it exits, it throws the trailing-point switch so as not to derail. The corresponding switch at the other end throws at the same time, insuring that the train will be routed back onto the same track. As the train passes the common section of track, it operates the reset relay, which releases all the arming relays. This in turn releases all the power relays.

As the train re-enters its siding, it operates that siding's arming relay, which latches. Then, as it reaches the other end of the siding, it operates the siding's power relay, which has been enabled by the arming relay. This supplies power to the stop section for the other train. An instant later the first train comes fully onto its stop section, and stops. Then the cycle repeats with the second train, and so on.

[dbaker48]

Thanks Bob!!!!!  I was wondering if I should have emailed you directly.  I will give it a shot, I will let you know how it works out.

Thanks !!!!!!

[jefelectric]

Don,  If you are looking for something ready to go, check out these sites.

http://www.three-rail.com/3RHOMET.HTM

http://www.z-stuff.net/

Not sure if they have what you are looking for but they do have some neat stuff.

[c50truck]

Thanks Bob!!!!!  I was wondering if I should have emailed you directly.  I will give it a shot, I will let you know how it works out.

Thanks !!!!!!

Don, I'm glad you asked on the forum instead of a private email. I was able to learn right along with you this way.

Rod L

[lionelsoni]

Ron, occasionally folks will e-mail a question like this; but I almost always post the question and any answer I can give anyway for just the reason you mention.  So you wouldn't have missed out in any case!

[dbaker48]

I have to be honest, I was really waiting for Bob to reply, I thought he would.  He and Roy have been extremely helpful when questions of this nature have come up.  Also, John (jefelectric) has been a big benefit.  There is a HECK of a lot of knowledge, talent, GREAT guys on this Forum.  Too many to mention all of them.