Originally Posted by: jpklecker@yahoo.com 
Requesting assistance in converting a Roco 14183A / 14070A BR 601 (VT 11,5) TEE train from AC to Märklin Digital. The motor is located in the front unit but both the front and back / end units have collection shoes which switch over with direction of travel. Upon inspection the motor appears to be AC as there does not appear to be any permanent magnetic field, it is a cylindrical piece located between the two sets of drive wheels (front of lead unit and back of lead unit). There is a black box next to the motor which appears to control the direction changes as well as where the power is accessed from (front or rear of train). The top of this box is labeled: 3023 SOS Relais DR-L-12V and it has wires coming out of it connected to the left and right side of the motor. I suspect the connections to the sides of the motor are for field windings each in a different direction like the field coils for the older Märklin AC motors. Piece of additional information - the cars are connected via a current conducting coupler system so the power from the rear collector shoe can provide power to the motor when the train is running in reverse. Also there is limited space beside the motor.
Hello John,
I read your post re your Roco 14183A H0 DB TEE VT 11.5 (made for “3 rail”) with interest and with a short trip for me down “Memory Lane”.
I was quite taken with the VT 11.5 set when it was first brought out by Roco in the ?late 1980’s?, available in “3 rail” version, so much so that I bought one via a retailer in England (snail mail, no internet, no parcel tracing, much by ship, long transit time).
It may well be that yours is a later version than mine, but the format you describe is the same. The train had only one motor. The motor is a DC motor (as indicated by
river6109 and
ktsolias), since the “AC/3rd rail” version is adapted from the standard Roco version that is a DC “can” motor (hence you see no brushes or magnets as you note; it is all concealed in the "can").
It was analogue but with an electronic reversing unit which also changed over whichever pickup ski was active. The electronics changed the “3 rail AC” current to DC (rectification, as pointed out by
river6109) for the can motor and also distributed DC power for the coach lighting via the current-carrying couplers.
When I developed a digital layout in 1995 I converted the model to digital using the old 6080 Märklin decoder – this decoder had a continuous motor output of 800mA and a peak output of 1A, running the train well on my layout but this decoder could not change over pickup skis (no direction change adapters back then that I knew of !). I forget how I maintained the coach lighting.
Today there are much better options for conversion.
Here are some images of my old converted Roco VT 11.5 train controlled by the antiquated 6080 decoder running on my digital layout, back in the day :
When
Märklin much later brought out the 37605 - their beautiful version of the VT 11.5 / DB 601, I bought a unit which remains my favourite train. It is of all metal construction, has two motors and sound with all the expected pickup ski changeover and various functions including controlled coach lighting. I really like this model
:
My fond enthusiasm for the VT 11.5 persists now, years later.
There are many historic images and videos to be found on the net.
Märklin produced this interesting monograph about the train :
If I may be so bold as to supplement the excellent advice already given to you by
ktsolias, an esteemed member of this forum,
if you wish to convert the unit to Märklin digital :
- you will need to remove the original electronics (possibly keeping the part of the electronics board that may mount the light globes depending on your choice of train locomotive/control car lighting methods – see below)
- decide your choice of which brand of decoder you install and if you want sound or not.
- my own conversion preference (to each his own) would be with an ESU LokPilot or LokSound V4.0/5.0 M4 21 MTC fitted to an ESU 51966 “change-over-ski adapterboard”. The board receives 3rd rail power from the two pickup skis, from this the board then provides power to the motor power supply points. Your coaches' interior lighting could come from AUX 1 but if you keep the incandescent bulb coach lighting then if the total current requirement exceeds the AUX output of 250 mA, a miniature rectifier (drawing power from the track) and an ESU mini relay (controlled by AUX 1) will be required to provide the coach internal lighting power.
The ESU 51966 board will also provide power for the front and rear train lights (locomotive / control car at either end of the train) and will change these over according to direction of travel. If you are not comfortable or able in changing the incandescent bulbs of the locomotive/control car at either end of the train to LEDs , then retain the part of the original electronics board that mounts the original incandescent bulbs, but put in their place Marklin “digital” incandescent bulbs (part no. E610080).
P.S.
I do like your dogs
– they seem very happy chaps.
did they by chance come with a whiskey bottle?
or perhaps you might have received them
by FAX from the whiskey cave itself of
David Dewar 
.
Regards,
PJ
