Marklin Engine with running strip

[Anonymous]

I was wondering if anybody can offer some advice. I do not have a significant amount of knowledge, however, I recently acquired a very nice Marklin steam locomotive. However, it has a running strip underneath the body, can I operate this engine on a standard HO layout, or do I have to have a special type of track to allow the engine to function? Also, if I do not need a special type of track, can I remove the strip and have the locomotive still function?

thanks,
Brad

[lionelsoni]

Maerklin trains run on HO track, but use AC voltage and a center rail, like Lionel. However, Maerklin's center "rail" is in the form of a series of studs rather than continuous. These are called "pukos", which is short for German "punkt kontakt".

Maerklin reversing is done with a higher-than-normal pulse of voltage, rather than by interrupting the voltage to the track.

It will probably be very difficult to run your locomotive on a 2-rail DC HO layout, mostly because of the need to insulate the wheels. The other electrical changes are relatively easy, however.

[FJ and G]

I always have wished that Marklin would make slider adapters for 3-rail trains and produce stud rail track for us.

At least one modeler has made his own.

Dave Vergun

[Anonymous]

Thank you so much for responding to my email on this topic. You mentioned that the electrical changes were simple enough to alter, how would you go about doing the alterations to make sure that the locomotive will run smoothly on standard 2 rail HO track?

Thanks,
Brad

[lionelsoni]

I have found a posting that does a pretty good job of describing what's needed:
http://www.scintilla.utwente.nl/marklin/archive/September02/msg00055.html
However, I will try my hand at describing it again for you here:

The Maerklin motor is a "universal motor" similar to that used by Lionel and American Flyer. It has a rotating armature winding and a stationary field winding, which are connected in series. Therefore, the same current flows through both windings. Since the motor's direction of rotation depends on the relative directions of the currents in the two windings, the rotation direction does not change when the direction of current reverses, because it reverses in both windings at the same time. Thus the motor runs in the same direction whether the current is DC or AC and whether you reverse the current slowly or rapidly, as with AC.

In order to reverse a universal motor, you must reconnect either the armature or the field (but not both) in the reverse direction in the circuit. That is what the Lionel e-unit does. Some cheaper Lionel locomotives have two field windings, wound in opposite directions, so that the e-unit needs only to select one to do the reversing. This allows for a simpler e-unit. This is also the scheme used by Maerklin. The common field-winding connection is wired to one of the armature brushes; and the reversing unit connects alternately to one or the other of the other terminals to select the field-current direction.

Lionel and American Flyer e-units step when voltage is removed from the track. Maerklin steps when a high-voltage pulse is applied to the track.

Most scale locomotives use motors which have permanent magnets for the field rather than the wound field of a universal motor. These will not work on AC, because the field direction does not change in synchronism with the armature current. They can be reversed simply by reversing the polarity of the DC however; so no reversing unit is needed.

A universal motor will work on DC without any modification. But, to get the usual scale-model reversing in response to the DC polarity, you have to do something to keep the field current from reversing when the armature current reverses. This can be done by installing a diode in series with each of the Maerklin field wires that would have connected to the reversing switch, so that, when the current flows one way, it flows through one winding and, when it flows the other way, through the other winding. These diodes replace the reversing switch, which can be removed. (There are other ways to do it; but this is the simplest.)

[BR60103]

Just for the record: the "running strip" is called a "skate".
Good luck with trying to insulate half the wheels on your loco!