power needs for 2 engines

Discussion in 'G / O / S Scale Model Trains' started by yronbay, Sep 10, 2004.

  1. yronbay

    yronbay New Member

    Hi folks. I have an MTH John Deere PS/2 set (MTH 30-4094-1) which came with a 75 watt transformer. I have ordered the DCS upgrade (50-1001) and an additional engine (MTH 30-2283-1) to expand my layout. The DCS will supposedly allow me to control each of these engines individually on the same layout. My question is - will I have enough power from the existing transformer or will I need more power in order to have both trains running? I plan to have each engine hauling about 8-10 cars. The second train will consist of several lighted passenger coaches, which I assume could play into the power needs as well. By the way, the layout will be created using MTH's RealTrax. If 75watts is not enough, how much will I need? The DCS upgrade, not to mention the additional engine & cars has already blown my 'hobby budget' through the roof, so I'm hoping I don't need to also add a big expensive transformer to this picture.
  2. jon-monon

    jon-monon Active Member

    75 watts at 15 Volts is a whopping 5 Amps. I would be surprised if 5 locos would draw that much but I don't know what scale you run, and bigger is more. Still, I would bet two locos would draw less than 5 Amps before their wheels slip. What scale do you run?
  3. yronbay

    yronbay New Member

    Sorry, this is O-scale, 3-rail. I thought the MTH names would be a giveaway on that. Thanks for the input!
  4. yronbay

    yronbay New Member

    Hey, I just noticed your personal data. Where is Cobblers Knob? We frequent a Pizza King Station on Charlestown Road in New Albany. My 2 boys love going there because of the train that brings out the drinks!
  5. 3railguy

    3railguy Member

    Figure 2 to 3 amps for a twin motor diesel. 1/4 to 1/2 amp per lighted pass coach. Your 75 watt transformer should only be maxed out at 75% which is 60 watts. This works out to 4 amps at 15 volts. (60/15=4) I would guess you are overloading your transformer and should go with a larger one. It suppose it wouldn't hurt to try the 75 watter and see if it blows the breaker or gets hot. If you buy a larger transformer, you can designate your 75 watter to accessorys.

    It's difficult to come up with hard numbers because different engines, lighted passenger cars, the number of cars you are pulling, operating conditions, etc. All affect amperage draw. This is why an ammeter is a good thing to have.

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