Automated train runnig and block control using isolated track sections

[cruikshank]

We are in the process of wiring up a club layout for mutliple trains starting and stopping using isolated track sections as stop tracks and trigger tracks.  The stop tracks have a center hot rail connected, but no common or outside rail connected.  The trigger track is Gargraves which isolates both the outside rails from one another.  There is a wire from one outside rail to the stop track.  The other rail has a common attached to it.  When train wheels bridge the gap, it sends a common signal to the outside rail on the stop track, starting that train out of a passing siding.  This is the old way of doing things, since the 30's.  We have several sidings, several triggers, and several stop tracks.  Here's the problem we have run into.  When a Passenger train, enters the stop block, the train fails to totally stop, because the rollers for the lighted passenger cars bridge the gap, intermittantly.  Hopefully this will make sense to someone, and they can tell us of a work around for this.  Other than this problem, the system works.  We also need more power.  We are using an 180 watt brick.  When three trains try to run at once, it is not enough power, works fine with 2.  Thanks in advance for any feedback.  Dave

[dwiemer]

I have seen some electronics companies advertising in either CTT or OGR, having some type of relay for such situations.  Perhaps that would help.  The other option, though more labor intensive, would be to lengthen the sidings to accomodate a full length passenger train plus extra space for stopping distance.  As to power needs, what about using blocks with two phased power bricks?  You may have issues with slow moving passenger trains while crossing the blocks, but if you keep up speed, you should be alright.

Dennis

[USNRol]

I would be careful you don't over current the wiring inside your passenger cars while they bridge between blocks.  I think the dual roller pax cars are connected via a common wire and usually two lamps.  The second roller helps eliminate flickering.  A fix for your problem could be modifying the pax cars by eliminating the common connection between the two rollers and making each roller independently power the lamp on its end of the car. (This may only require snipping a wire!) When stopping with a modified pax car bridging the two blocks (the un-powered one and the powered one) only one lamp in the car would light; the one attached to the roller currently positioned over the "Hot" block and since the two rollers are not connected anymore the pax car wiring will not be transferring power to the un-powered block.  See?

Roland

[lionelsoni]

Dave, I'm puzzled by your description of the problem.  I don't see how having pickups for lights would make a lighted passenger car behave any differently from a freight car, since the gap is in the outside rail.  I would think that any metal truck would cause the problem you describe.  Metal couplers and car frames can exacerbate the problem.  You can also burn out knuckle springs that way.  I use the scheme you describe, but the trains on that track have plastic drawbars and couplers.

Going across center-rail gaps between separately powered blocks is another problem and can be a fire hazard.  I had always thought of dual pickups as an anti-flicker measure.  But when I opened up some Williams cars to put in capacitors, which is my favorite alternative to dual pickups, I discovered that the two lamps were not connected together but each had its own pickup!  I wound up rewiring the cars with two bridge rectifiers and a single capacitor, keeping the pickups isolated but each feeding DC to both lamps.

[trigtrax]

Here's the problem we have run into.  When a Passenger train, enters the stop block, the train fails to totally stop, because the rollers for the lighted passenger cars bridge the gap, intermittantly.

It fails to stop but not for the reason you've given. The rollers bridge the Hot track it's the conductive car body that's bridging your Common tracks.

You are working with a totally "passive" control system. In essence the wheels  of the trigger train are acting as switches for the cold side of the stop block. The ambiguity of this is your second source common supply, the wheels of the stopped train. I'd suggest using an "active" control, a relay. Use the common rail switch to control the Hot Rail of the stop block through the relay. Radio Shack sells a 30 Amp automotive relay for about $5. Power this through a 1N4001 diode in series to your common track.

Oddly enough I used to manufacture a device called Trigger Trax, a bit more advanced than a common relay because it had a latching feature and required one trigger to set it and one to reset it. I quit producing these contraptions when TMCC showed up because cutting power put the remote control engine into neutral and required operator intervention to get it rolling again. So much for automatic operation

I still use my Trigger Trax module on my Catenary Demo board. It turns on a Banjo signal as the engine rounds one curve and turns it off when the engine gets to the opposite side of the board. Devices like that lead to precise control for automatic operation. You should contact Burns Manufacturing (A CTT advertiser) as he is still producing devices of this type.