Peassenger Cars with
RTS Electric Couplers
To light passenger cars, normally every car must have a pickup shoe. Because of that the trains are hard to pull and some locomotives had problems uphill. Alternatives are electric couplers from Maerklin, Fleischmann or Roco. All of them has a disadvantage. The four-wire-coupler from Roco is expensive and for an simple passenger interior light is only one wire needed. The tqo-wire-coupler from Fleischmann ist expensive too, and the decoupling ist complicated. The electric coupler from Maerklin ist cheaper, but very hard to uncouple. Sometimes the wing of the couple can be damaged.
The company RTS has electric couples, that be based on the Maerklin short couplers. Instead of a pre-decoupler it has a metallic spring. Only one coupler of a pair has a shackle, but the other one can be retrofitted. This shackles must be ordered separatly. The RTS ouples looks liks short couplers, but it couples not so soft, because of the spring for the electric contact. If two cars are pushed by hand together, the coupling works at once. Doing that with a locomotive "by playing", it doesb´t work. The other car rolls away.
To decoupling ist not problemfree, too.. Often the normal short couplers are hard to separate on decoupler tracks. If the train is pushed together to relieve the couplers, it works better. The same problem has the RTS couplers, but the contact springs makes it harder. If the train is pushed together by hand or by a second locomotove, it is possible to separate the cars on a decoupler track.
The installation is quite easy. The RTS couple will be sticked into the hole, like other couplers. If the cars had the Märklin electric couples before, it has a second contact spring inside. No additional wireing is nedded. RTS recommend at other cars to put a wire with the coupler together into the hole. I had bad experience made with that. Sometime the wire jammed in the hole and the electric coupler will not fit, sometimes the wire was slack and had no contact. The best way ist to solder a wire directly to the spring (green arrow). The electric contact between the RTS couplers is well, there are no loose connections.
Some cars has less space between the coupler and the bogie. By driving S-curves, the coupler and the bogie are jammed and the car derails. The RTS coupler has the contact spring, which is a bit longer (orange arrow). This is the reason for many derailings. With a pair of pincers I cut the red colored parts. The stability of the bogie is good enough. The axle is hold by the clamp in the middle.
Some cars, like the "silverfish" from Roco has less space from one care to the other. The end of the cars touches together before the couplers can click into place. The solution ist to put the couplers not with its full length into the hole and to fix it with some solvent-free glue.
I used here my selmade made interior lights. The costs are only 1 DM each car. Like shown at the photo, I cut small pieces fram a circuit layer and soldered the bulbs onto. After that I glued it under the roof and wired it. It looks difficult to solder inside the car, but ist is not. Some of the 24V bulbs became hot, but the there is no danger, that the roof will smelt. Additional I paste a piece of adhesive tape which is permeable to light. With this I eleminate the light spot under the bulb.
The car is even and well iluminated, like the photo shows.