catenary ho

why does locomotive run slow on catenary and faster on two rail system.


  • Hello David

    Welcome to our Forum.

    Are you operating an analog or digital layout? If it is digital, it is nice that it runs, in the first place.

    Are you using the same power supply for both, tracks and catenary?

    What brand and model is your locomotive?

    You see, there is no blanket answer to your question.

    One possibility is that the voltage drop through catenary system is greater than the drop caused by the rails. But this is only one out of many possibilities.

    You see, we need more info.Choo Choo2015-02-18 23:46:51

  • I am using same locomotive and power supply for catenary and two rail system. I want to know if this is a common problem with catenary and can the problem be solved?
  • It is not a common problem.

    Is your layout digital or analog?

    What is the make and model of the locomotive?

    What is the make and model of the power supply?
  • Hello:

    Welcome to the forum.  What type of catenary are you using?  I assue that you use standard DC-track.  The reason for the different bahaviour is the way track and overhead catenary conduct electricity.  While railjoiners usually conduct electricity decently well (untill they get loose), the catenary pieces rely on the way they touch one another.  The latter should result is a higher resistance, and thus a higher voltage drop.

    One way to solve this is by soldering the catenary pieces together and, have several spots where power is fed into the catenary system.  Also, you might try to run your locos with both panthographs up.  This may take care of some of the problems since the current flow down a panto may encounter more resistance than the current from the track.

    Finally, if you decide to go DCC, then the whole issue goes away.


  • what if I use a separate transformer for the catenary and another one for the single rail, would this increase power to the catenary system?

  • how does the problem go away if I use dcc?

  • If you switch to DCC, the problem goes away because the pantographs of electric locomotives with a factory installed decoder are not wired to pick up power, because of the inherent problems.In a digital environment good conductivity is more critical because of the complexity of the digital signal. This signal does not only provide the electrical power, it also carries a binary signal like computers use. In this case a catenary system is merely for show.

  • Okay, I think there is a basic misunderstanding here.
    In the past, modelers used live catenary power as a means to be able to operate two trains independently on the same section of track.  I planned to do that on my previous layout.  The plan was to have an electric switcher working off catenary.  That would have allowed the switcher to enter track sections on which other trains were stopped.  I tested this on a small section (with some ugly non-ptrotypical catenary), but never got much further prior to a move -- and the dismantlight of the layout..
    With DCC, there is no reason to run anything off live catenary.  All power is fed through the tracks, and you can operate any number of locomotives independently on the same section of track.
    The reason the problem of bad power feed with live catenary will go away with DCC is that you no longer have any power feed through the catenary.  There simply is no reason to have live catenary, as there are all sorts of problems with reliable power feed through catenary -- which are not encountered with power feed through the tracks.
    Hope that makes sense.
    -- Ernest
  • Dear Aaron:

    When operating a DCC layout, all power is fed over the rails (and the studs if you use Marklin).  Feeding the power over the overhead catenary makes no sense in this case out of several reasons:

    a) Since the power pick-up through the wheels and rails is more reliable than through the catenary and panthographs, there is no need to feed power through the overhead catenary when using a DCC system.  The electric locos will pick up power from the rails just like your steamers and diesels.  The capacity of DCC systems is large enough to handle all this traffic.  Moreover, overhead catenary power adds an unnecessary complication when running your electrics through a return loop, unless you have Marklin track.

    b)  In an analogue system, the overhead catenary and one of the rails form a second electric circuit with a common return (one rail in DC, both rails with Maerklin).  If you carry this idea over to the DCC world, and try to boost capacity by running two command stations (one overr the rails and one over the catenary), then you are asking for serious trouble since you would operate two command stations with a common return, something all DCC manufacturers warn against.  Even with boosters, it is not recommended to have a common return because of possible interferences.  Most DCC manufacturers strongly advise against any such common rail wiring too, and recommend that power district are separated in both tracks.

  • Markus:

    If you use the old Marklin catenary, it oxidizes, and the resulting product is a lousy conductor.  When I ran analogue, I ran all my engines with both pantos up if they picked up power through the catenary.  Even then, it was not a completely satisfactory experience.

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