Diodes, first post.

Discussion in 'FAQs' started by Sempak, Jun 19, 2002.

  1. Sempak

    Sempak Member

    Hi all,
    This is my first post to the forum so I decided to offer something i recently discoverered, this may have been said before but I can't see it.

    On my first layout with powered points i used a common negative wire and two positives. I had no CDU so the trains slowed down every time the switch was changed and I needed three wires.

    By two diodes I discovered that you could use only two wires and have the direction controlled by the polarity...

    --Chris (Sempak)

    Bio: I am 14 and live in Melbourne, Australia my dad bought a HornbyThomas The Tank Engine set when I was about eight but it never got assembled until I was 11 ;). I now have a 'work-in-progress' 8' x 6' layout still using some of the original track but also some Peco flex, Peco 18" curves, Peco points etc. My local trains shop stocks a lot of Peco stuff!

    Attached Files:

  2. Woodie

    Woodie Active Member

    Hi Sempak!

    Hi Sempak! Don't you worry bout those other lot on here. They don't talk to foreigners like us!!:D :D They're not a bad lot, but! :rolleyes: They're a good bunch, really!

    I think they call what you've designed, a sorta "bridge rectifier".

    For switching my points, I use the AC outlet on my controller, so it doesn't affect the trains at all, but I know what you mean about the threee wires. I run a "common" wire to all my points (turnouts) too, and then another two wire to each (one for each coil on the point motor.

    Have you "cooked" any point motors with you diode method?

    BTW. I'm in Sydney. Just sorta "up the road" :cool: .

    Was in Melbourne a few weeks ago for the footy. Swans V Collingwood. Hey, you know Colonial Stadium, well, if you go over to the north west corner (the start of Footscray Rd) there is a red brick building on the corner (Dudley St & Footscray Rd) I think it's that corner
    Well, they've got the most hugest layout in there. Takes up the whole building! Click here to check it out. Well, that gives you the address and stuff, but their website (which WAS there last time I looked), seems to have gone.

    Anyway, good to see another local on the Forum, and let's know how your layout is going. :cool:
  3. Sempak

    Sempak Member


    I think a bridge rectifier is a way getting AC or uncertain polarity DC into a set + and -.

    No, I haven't cooked any point motors because I still use a Capacitor Discharge Unit to supply the current. I got it from DSE for about $12.

    Next time I'm in the Colonial area I'll make sure to have a look at that layout.

    I don't have a digicam so my layout photos wont come until I finish my roll of film and develop it!

    --Chris (Sempak)
  4. Woodie

    Woodie Active Member

    BTW, Sempak, who are you using as your "local train shop"??
  5. Sempak

    Sempak Member

    490 Dorset Road,

    I can't remeber the phone number off the top of my head my I'm assuming you know how to use www.whitepages.com.au or a phone book!

    There is a Train swap meet on tomorrow (Sunday 23rd of June) at a local scout hall so I'll probably be there... :)

    --Chris (Sempak)
  6. Woodie

    Woodie Active Member


    kewl! When in Melbourne, I usually check out Vic Hobby Centre (Swanston St), Trainworld (in Caulfield) and Hearn's Hobbies (Flinders St). Ain't been out to Branchline yet.

    I'm currently building myself a set of old Melbourne "red rattlers". Taking a bit of time and effort though!
  7. Bob Collins

    Bob Collins Active Member


    I think you have a very bright 14 year old on your hands and he is going to teach us all. Of course, I haven't understood a word either of you has uttered on this thread.

    I'm wondering if planning a train trip between Melbourne and Sydney (Colonials???) is worth planning into our trip. If so, which direction so it is light when we travel.

  8. Sempak

    Sempak Member


    I think you have a very bright 14 year old on your hands and he is going to teach us all. Of course, I haven't understood a word either of you has uttered on this thread.

    I'm wondering if planning a train trip between Melbourne and Sydney (Colonials???) is worth planning into our trip. If so, which direction so it is light when we travel.


    I was looking through my old posts and came across this one which never got an answer.

    Colonial refers to the name of a stadium located in melbourne. For anyone planning a trip, melbourne is several hundred kilometres south of sydney on Australia's east coast.

    I now do some casual work on the corner os Collins and Swanson street so I've checked out the VIC hobby centre and I'm planning to check out hearns hobbies next time im there.
  9. Bob Collins

    Bob Collins Active Member

    Goodness, this is an old posting. I have since been to Melbourne, even on the corner of Collins and Swanson and I rode the XPT from Melbourne Spenser Street Station to Sydney.


    Attached Files:

  10. jon-monon

    jon-monon Active Member

    Hi Chris, (g'day) belated welcome to the gauge! Don't listen to woodie, bless his sole, when he says us gringo's don't talk to you all. We love to hear more from you and maybe see some of your modlin'! :D :D :D
  11. Bob Collins

    Bob Collins Active Member

    Wonder why only half the pix went the first time? Here is the full pix (I hope) of the XTP pulling into the Spenser Street Station in Melbourne after it's overnight run from Sydney. We departed on it a few minutes later for the 11 hour daylight run back to Sydney.


    Attached Files:

  12. shamus

    shamus Registered Member

    Hi Chris and welcome to the gauge from the UK.

    The reason your loco's slow down is because power is used for the point change over, and is taken away from the loco whilst running.

    Always better to use a 24 volt transformer through a CDU and a seperate transformer to operate the loco's.

  13. Sempak

    Sempak Member

    I do have a separate transformer and CDU for the points. That was a very old post and the diagram shows how I have it all set up.

    I was looking through my old posts after taking up the hobby again after illness and saw that Bob had posted a question that went unanswered.
  14. Pitchwife

    Pitchwife Dreamer

    solenoid points

    Hi Chris, welcome to the Gauge.

    Although I don't have anything built yet I plan on using a different method for switching points. I am going to use spring loaded solenoids with a flexable wire. I found some for about $1.50 each. They are rated at 24 vdc intermittent, so I believe that I can get away with 12 vdc (which the supplier claims that they would work with) over a longer period. They are going to be mostly used in the staging yard and having the "relaxed" position in the predominant direction of travel. They will be mounted on the underside of the layout with only a small hole for the lever, kind of like a switch machine only faster and cheaper. :D The other plus is that all I have to do is run a common ground from one to the next etc. Then it just takes a single wire from the other pole of each one run to a switch on the control panel which is connected to the seperate dc power supply. The only problem that I'm not sure of yet is muffeling the noise they make when activated. Probably some sort of mounting dampers. I don't know if anyone else does it like that, but I don't remember seeing anything about it.

    Just a thought

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