Making a train go foward and backward

[Curt]

I am wondering how to make a train go foward on a short distance of track and then switch and go backward on that same track. I have seen it done and have always wondered how it is done.

[Curt]

Yes I meant it switches automatically

[Wayzata Modeler]

 

I would think that a switch trigger would be installed in the track bed that would be thrown by the foward moving engine - the switch would then reverse the polarity on the track

[IRONROOSTER]

Here's one control unit to do this. http://www.walthers.com/exec/productinfo/800-5400

I'm sure there are others.

Enjoy

Paul 

[TheK4Kid]

http://dallee.net/PDFs/DalleeCatalog43CombPkgs.pdf

google is your friend.

David B

 

Thanks, I want to do this with a set of trolley cars I have, but they will be on a totally separate power supply and separate track from my layout. 

[MisterBeasley]

Is this a DC or DCC locomotive?  That's the crucial question.

DC, in this case, is the easy one.  All you have to do is find a way of automatically reversing the polarity of the voltage going to the track, probably using a relay triggered by a sensor when the train gets to a certain point.  For DCC, though, you would need to interact with the DCC signals, a much more difficult proposition.

Somebody has a commercially available trolley car system that does exactly this.  It's DC.

Who remembers the old Lionel "Section Gang" cars?  These were self-propelled "scooters" with sturdy bumpers on each end.  When they hit something solid, they would reverse direction and go the other way.  This was all accomplished by putting a reversing switch in the car which could be physically thrown by banging the car into something.  You might be able to devise some sort of "kindler, gentler" circuit with a magnetic reed switch.

[ndbprr]

Some of the more sophiticated methods add a delay at the end.  This would allow your 1/87 passengers time to disembark or board before going the other way. 

[BigG]

  Hi Mr B.      My old Marx loco only needed the AC to be interrupted for a fraction of a second to auto reverse. Darned annoying when all I wanted was to stop for a bit, then proceed fwd. Glad the modern stuff has improved on that...      For the electronic whizzes amopng us, you should be able to get auto reverse with a flip-flop and a relay and a hefty capacitor circuit.

[larak]

Here's another link for you Curt.

http://home.cogeco.ca/~rpaisley4/CircuitIndex.html#Reverse

You definitely want the train to stop and pause at each end. It not healthy to suddenly reverse a moving train!

Let us know how you make out.

Karl 

[loathar]

http://www.ittproducts.com/irpage.htm

I think this is another circuit where you can adjust the pause time at each end of the route.

[ndbprr]

I do have one question though.  If you are going to use a trolley what are you going to do about the pole that will be backward for one run?  You might do better with a couple of loops at either end which would also require some form of switching or you could just make it a big loop and have it go to different parts of town in which case you wouldn't need anything other than power.

[topcopdoc]

Good info! I have a commuter line with RDC's and MP54's and several stations. This could enable me to run the commuter cars automatically while I concentrate on running the passenger or freight trains.

Ultimately my goal is to run six trains at the same. I have a long tunnel where the trains could hide for a few minutes creating the appearance of a longer trip.

Thanks Doc 

[Anonymous]

Im wondering why you would need that?

[Gandy Dancer]

You definitely want the train to stop and pause at each end. It not healthy to suddenly reverse a moving train!

I've proven that not to be true.   I made a display to promote the RTD NE light rail expansion here in Denver.  The unit did not stop but just reversed directions.  The city people run the trains way too fast, such that the loco skids when the direction switches.  I go and slow it down, they come and speed it back up.  The locomotive is run non-stop for two day exhibitions all the time.  It is displayed an average of once a month.  The module has been in use for almost 6 years now.  The run is 16 feet so it has more reverses than any of my fleet will ever see in their lifetime. 

[larak]

Pretty amazing! Not even a broken coupler after six years? Maybe the skidding and possible wheelspin takes up some of the force. Maybe you've been lucky. 

Still, it wouldn't be prototypical. Or would it? What fun embarking and disembarking from a real train at the exact second that the motion is zero.  And just imagine the banging and clanging.

[MisterBeasley]

I'm not saying this is going to be the most cost-effective option, but...

How about computer control using DCC?  I haven't hooked a computer up to my layout (yet?) so I'm not familiar with the available software.  But it seems to me that you should be able to do this sort of thing.  It would require a sensor at each end, but then the computer could be in charge of deceleration, delay, direction change and then acceleration again.

Which DCC systems support this kind of thing, and what software (payware/freeware?) is recommended?

[Bobster]

Greetings,

 

  I would like to suggest you use a timed stop.  The hobby shop I used to work at burned up several HO trolleys because people would come by and turn up the speed. We had the skidding problem too when going fast. People would put their fingers over the light sensors to make it reverse after only a couple inches of travel to see how fast it could switch directions.  We found instant reverse was not good for the motors or gears.

We also had a Lionel that reversed when its bumpers hit the end stops. Its survival was much better.

Good luck,

Bob 

[Gandy Dancer]

Pretty amazing! Not even a broken coupler after six years?

What would there be to break a coupler?  These are trolly cars and not coupled to anything.

I agree that stopping is a better idea, but it either increases the cost of buying or complexity of building the electronics greatly.  The age old question of cost vs. quality. 

[larak]

Pretty amazing! Not even a broken coupler after six years?

What would there be to break a coupler?  These are trolly cars and not coupled to anything.

I agree that stopping is a better idea, but it either increases the cost of buying or complexity of building the electronics greatly.  The age old question of cost vs. quality. 

Actually the original post asked about trains NOT trolleys. So does the post title. I would think that the coupler on the first car would be under a lot of stress at reversal time. I guess it's easy lo lose track of the original post as these threads wander about.

 

[trainboy414]

i found an easy way to do this is to put a dpdt slide switch under the engine or trolley and wire it in it in to the main wireing but this means you can only run this on that track.yYu put a small piece of wood or styrene in the track so the dpdt switch his it.

[Gandy Dancer]

Pretty amazing! Not even a broken coupler after six years?

What would there be to break a coupler?  These are trolly cars and not coupled to anything.

Actually the original post asked about trains NOT trolleys. So does the post title.

Yes, but the example from which this was a comment to was a trolly.

[larak]

Pretty amazing! Not even a broken coupler after six years?

What would there be to break a coupler?  These are trolly cars and not coupled to anything.

Actually the original post asked about trains NOT trolleys. So does the post title.

Yes, but the example from which this was a comment to was a trolly.

No it wasn't. It was a response to the original question. Notice the use of the OP's name and the word "train" twice in my post. I am sorry if you misunderstood, but you did misunderstand. Suck it up and move on. This has become pointless.