Automated layout..

Discussion in 'FAQs' started by csxengineer, Jan 25, 2004.

  1. csxengineer

    csxengineer Member

    Ok, bear with me..
    When I was very young my neighbor had a 4'x8' HO layout ( no scenery) with various loops and elevations. I remeber seeing 1/2 inch-1 inch pieces of atlas track that were I believe insulated on each end and wires solderd to it. I belive that when he ran a train onto this section, it would trip a relay that would route the next switch for it's movement. The layout ran 2 trains without any conflicting moves or accidents. He was an electrical engineer, so this never suprised me. Any idea how it was done, and how could I duplicate that concept. EASILY, CHEAPLY, AND IN PLAIN ENGLISH!!

    Thanks friends.
  2. belg

    belg Member

    The short answer to this is that there is NO easy way to accomplish this as all the switches would have to be wired very careful with either optic sensors or contact switches neither of which is a beginner electronic project. The first thing I would reccomend is to get your track plan as thoroughly mapped out as you can and maybe get some of the items I mentioned above and work on them of your layout to see how they work. Also get some books on wiring your layout and I'm thinking this will not be covered in the basic wiring section. Good luck and don't be afraid to ask specific question on how to do certian tasks. JMHO Pat
  3. ezdays

    ezdays Out AZ way

    Someone could use that short section of track and wire it to a relay. When the loco hit that section, it would rely on the wheels to carry the voltage from the other tracks to operate the relay. Your engine would have to pick up the votage from more than one set of wheels, and they must be farther apart than the small section of electrically isolated track. But as Belg says, it is not that easy to accomplish, especially at varying voltages. For example, if you were running at a slow speed, say around five volts, you wouldn't be able to trip a 12 volt relay. On the other hand, if you used a five volt relay, you would quickly burn it out operating it at higher speeds, say 12 volts.

    Belg is right, there are better ways to do this although it is not out of the question.
  4. TR-Flyer

    TR-Flyer Member

    Hi automats:

    Don't forget, you will also need the ability to stop a train at a turnout and have it wait for the other one to pass through as they will eventually, inevitably, end up at the same turnout at the same time. This kind of thing is easily done with O-gauge three rail track. It's a lot harder with two rail. Current sensing is one of the most reliable ways to tell a relay that an engine is passing through a particular piece of track. IR detectors, photocells and reed switches are others.

    The 1-inch track section can work, as long as all your engines pick up plus and minus current from both trucks. Put another way, it won't work if the front truck picks up negative and the rear picks up positive. I believe the engine will die in the "dead" section.

    Good luck, post a note if you figure it out. I'm looking for a cheap way to do the same thing in "S".

  5. ezdays

    ezdays Out AZ way


    If the short section has reversed polarity, when the front truck hits this section, it will put a direct short on the power pack. Some power packs can take a sustained short, and will sumply shut down while some aren't as forgiving and will heat up quickly.

    One would also need a way of programming different switching arrangements. Tricky to say the least.
  6. 60103

    60103 Pooh Bah

    One way to do this is to have a completely separate transformer from your track power. Your track power will need a common rail, which will be the rail that you put the insulated sections in. Wire one side of the transformer to the common rail and the other, the short sections are wired to one side of the relay/switch machine, and the other side of the relay goes to the other side of the transformer.
    Hornby made a train control system, about 30 years ago, using this sceme. They had a contraption that held a brass contact just clear of the rail and the wheels pushed it down.
    You cannot use this method inside a reverse loop, as the common rail does not exist.
  7. Lightbender

    Lightbender Member

    Hello Csxengineer,

    Dave mentioned wipers which is the right idea for doing this cheaply. There are a few electronic solutions but I can't think of any cheaper than simple analog switches and snap relays. The isolated track would be killed by a wiper hitting a momentary switch between the tracks tripping the relay. Having the switch offset would avoid hitting it going the other way. Magnets and reed switches can be disguised better but cost money. The momentary switches can be easily home made. How many snap relays you need depends on what you want to do on the layout.
  8. Fred_M

    Fred_M Guest

  9. Lightbender

    Lightbender Member

    Hello Fred,

    Thanks for the link, looks like they have some fun stuff. Of course once you have a computer in the system the solutions become far more elegant. My suggestion of locomotive tripping switch and relay is an under $10 fix for this problem but it would not be particularly attractive in action.

    Using a computer the approach speed can be more realistically slowed and then ramped up after the other train has passed and the turnout switch changed. Of course your solution also allows much more to happen than just this meet, an entire operating session could be programmed.

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