Märkllin 3103, KPEV T 12 7896
Märklin 3103 after the conversion
Preparations for the conversion:
First of all, remove the reversing unit and the motor from the locomotive. Also remove the pick-up shoe and it's contact plate. Make sure that the locomotive works perfect mechanically, like the gears, wheels and connecting rods. Clean it well before installing the new parts. Carefully oil the rotating parts - if required.
The Märklin 3103 inside after the conversion
Conversion sets for Märklin 3103:
As this model has a Small Flat Collector Motor (SFCM) Märklin conversion sets 60903, 60623 and motor set 60943 may be used.
The only difference between these sets is the decoder. 60943 has no decoder, a decoder must be ordered separately, for instance the 60962 decoder set.
Installed at the same place as the original reversing unit. Initially I used the mini c91 decoder (Märklin part number 603462), not the bigger 60902 decoder from the 60903 set.
Later the decoder was replaced by one from the SBB Ae 3/6 II 10.421, Märklin set 37512 (part number 102155 or 611573, I think). That is a remotely adjustable decoder with the same functions and the same size as the mini 60902. The reason for replacing was the maximum speed, which can be adjusted to a much lower speed than the potentiometers on the mini 60902 allows. With the mini 60902 the maximum speed at the lowest possible adjustment was approx. 160 km/h. Now, by adjusting the speed (CV5) to level 15 with the Central Station, the maximum speed is approx. 80 km/h. Perfect!
Installation of the motor itself is quite simple. The diameter of the head on the lower screw for the motor cover must be reduced. This is to avoid conflict with the rear left wheel flange. I used a small grinding machine to do this.
The photo shows the initially installed mini c91 decoder
The locomotive body is insulated with self adhesive rubber foam to reduce the motor noise.
The front lamp is installed in an old bulb socket (part no. 475030) glued to the front of the locomotive chassis, with a bulb socket insert from the 60903 conversion set.
For the front lamp I use 28 Volt T1 bulbs with wire ends, cut to suitable length. I think the 610080 (22 Volts) gives a too bright light.
For the rear lamps I drilled holes in the lower lamps and installed a light guide from the BR80 (3304, Märklin part no. 200690).
I made a bulb holder of some old plastic parts and a two-pole SIL socket. The rear lamp is a 610080, as the light guide reduces the light intensity.
A future improvement will be to rebuild the rear light light to LEDs, including the top lamp.
As seen on the locomotive photos on top of this page, my Märklin 3103 does not have the original couplers.
The front coupler is cut under the bumper beam , just in front of the air tank.
The rear coupler is rebuilt with a close coupler from the Märklin coupler set 7205 (40 couplers for cars and 10 for locomotives), by cutting the original coupler and gluing in a car coupler.
First I remove the moving parts from the coupler, then it's cut at the red or yellow line, depending on the required length.
After shortening the new coupler, and cutting off the centering springs, glue it
to the old coupler. Secure it by bending in the lugs.
Be sure to aligne the coupler properly.
The locomotive is meant to run in a consist with the four coach set 4035.
A black wire runs from the luggage car to the green front car, partly visible in the photos.
Behind the locomotive: 1235, next 1418, then 1604, finally luggage car 3103.
A Märklin 60960 function decoder and a relay is installed in the luggage car 3103 Pi.
The decoder functions, including car set 4035:
|function||Locomotive3103||Car set 4035|
|f0||f||3 front lights||-|
|r||2 rear lights||-|
|f1||-||interior light in the connected three coaches, via a relay|
|f2||-||interior light in conductor's cabin and one rear red light|
|f3||-||interior light in the luggage area|
|f4||acc/brake delay off||red LED inside the luggage area, just for fun|
Screenshot from my Central Station 1:
Information about the T 12 prototype, from Wikipedia:
|T 12 (Preußen, Elsaß-Lothringen)|
DR 74.4 – 74.13
ÖBB 674, PKP OKi2
SNCB 69, SNCF 130 TC
|Numbering||DR 74 401–543, 545–1321|
|Building time:||1902 – 1921|
|End of service:||1968|
|Length:||11.800 / 12.100 mm|
|Service weight:||65,90 t|
|Axel weight:||17,36 t|
|Max speed:||80 km/h|
|Power||640 / 669 kW|
|Driving wheel diameter||1.500 mm|
|Front wheel diameter||1.000 mm|
|Cylinder diameter:||540 mm|
|Piston stroke:||630 mm|
|Steam pressure:||12 bar|