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.

The two red wires on the top of "box" are connected to the motor

Hi
The motors are DC no question about that.

To convert it to Märklin digital you need to do the following thinks.

1. Check if there is enough space for the decoder base and decoder
2. Take of all the existing electronic modules and cables except the motors and the pick-up shoes
3. Use the 60973 decoder board which has the pickup Changeover
4. Do the connections according to the instructions
5. The motors must connected in parallel (if there are more than one)
6. You can use any 21mtc decoder you like with or without sound from Märklin or ESU

Regards

Costas

Thanks for the suggestions and help - greatly appreciated.

ktsolias: What do you mean by 21mtc decoder? Would a Märklin 60983 decoder be the type to use since from comments that suggest the motor is in fact DC with a permanent magnet? There appears to be no "brushes" for the motor as there are no openings in the motor casing - just the two electrical connections via the two red wires shown in my first photo.

The Märklin 60983 decoder has continuous current load at the motor output of <= 1.1 amps, maximum total load <= 1.6 amps.

The complete train has the two lights shown in the engine + 5 passenger coaches of 2 lights each + the end cab unit with two lights (total lights 14). The lights are all the same type as shown in the above photos other than the two for the headlights. It appears that all the lights are wired to remain on at all times, regardless of train direction. The only thing that changes is which collector shoe the power for the motor comes from - and this is transmitted through the train from the back to the front via the permanent couplers. A leaflet in the box states that for block operation the rear collector shoe must be removed and that the train can then only be operated in one direction.

I am not quite sure of how the electrical connections are working. The two black wires coming up from below the circuit board (upper photo front of circuit board) appear to be connected to the front collector shoe and the right side of the "little box". This also connects to the rear of the light bulb at the back of the unit which also has wires going down to the coupler. The wire at the front of the rear light bulb is connected to the left side of the "little box" and as is visible in the upper photo is grounded to the frame via a screw that attaches the circuit board to the frame. I don't know how both collector shoes can be providing power at the same time if they are both connected to the couplers...? Sorry - the wiring is confusing me.

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

Thanks so much for all the good advice and helpful tips. I have done some testing on the unit as a train in normal AC mode. The front (power) unit will run in both directions without being coupled to the train - so apparently there is not a change on the source of power when reversing. The coahces when connected to the power (front unit) have interior lights. When the coaches are connected to the rear power unit - and not to the front unit - they have lights. When the entire train is coupled together as a proper consist - they all have lights. The power unit lights do not switch with change in direction from front unit to back unit or vice versa. There is a note on the instructions that if the train is to be used running on tracks with blocks, the rear collector shoe must be removed and the train should not be run in reverse. It also indicates some connections to disable as well. Due to my testing, I would take this to mean that the train will not stop in an unpowerred section of track as the power would flow to the motor via the rear collector shoe while it is outside the dead section of track.

I was wondering if the 60973 unit from Märklin is used and the power connection between the coupler and the power unit were separated so the changeover will function, then the power coming from the back of the consist will not run thru the decoder before reaching the 60973. Due to this the lights in the coaches and the rear power unit will come directly from the track and not through the decoder. I could have the front light connected through the decoder so it would only be on when the train is running forward, and off when running in reverse. This would mean the decoder would only power one light - not the entire train. The bulbs for the coaches are actually tubular in shape with power connections at the ends. So using the Märklin LED bulbs would need some creative wiring in order to replace them.

Another question: I notice that 60973 has a series of pins on the top - does a decoder just slide onto these for connection? If it does, what decoder is best to use? I am not concerned about adding sound to the consist - there is very limited space in the power unit and don't think it would fit without major modifications.

PJ - the Scotties did not come with a whiskey bottle but were adopted from a breeder in Idaho. The wheaten one (Hexie 5.5 years) is a little pistol and loves to follow me around to see what I am doing at all times. The black ones name is Viceroy (13.5 years).

I want to replace the giant motor in Roco VT 11.5 TEE with a lower Amp unit. Suggestions where I might get one that fits in loc?
Ben