Classic UK Minitrix Models  -  Bogies and Pickups
The electrical stuff

Although the main chassis is similar in design to some of the Class 27 locos, the Bogies and pickups on the E112 have the same arrangement as those on the Minitrix Class 42.

This particular model had ground to a halt, and had been messed around with. The pickups were bent out of shape, consistent with someone trying to re-bend them to touch the inside of the wheels without removing them from their housing. This is rarely successful. The motor and gears were covered with oil, and the wheels were spaced too close together on their axles - the inside hubs were binding on the frame of the bogey and would not turn.

Here are the two bogies cleaned up with the pickup block removed. Both are bent out of shape, but the one on the left isn't too bad. The one on the right is completely wrong. Note that in this photo, the pickups are not paired with the correct bogey, although they will fit.

I believe that the block which clamps the pickup will separate - they appear to have plastic pegs which locates the position of the two halves. Since I didn't need to take them apart, I didn't investigate. Old plastic can be brittle and will often break very easily. Why risk it ?

Here are the two pickups after I had straightened them out. The photo shows them how they will be positioned in a loco facing to the right of the picture showing the four pickups (2 on each set) that brush on the inside face of the right hand wheels. The longer arm spring upwards and sweeps across a copper strip on the lower circuit board (not shown).

Note that these pickups are 'handed'. Although either will fit into either bogey. The trick is to get them so that they are both positioned on the same side of the loco.

The pickup before being fully seated. The long arm needs to be threaded through the space for the wheel, as shown, and care needs to be taken that it doesn't catch up on the bogey frame before the plastic block is pressed gently into position. Check that the wheel pickups are sprung towards the outside of the frame as shown, so that eventually they will press on the inside face of the wheels.

Here showing the bogey viewed from the centre of the loco with the sweep bent upwards to press against the underside of the lower circuit board. Note how the copper fits snugly over the vertical spar on the bogey (or it will be snug when the circuit board presses onto the sweeping arm.

Same bogey viewed from the side. Note the curve in the copper strip designed to clear the axle. The pickup is collecting positive power from the right hand rail (loco is facing to the right in the photo). The axle is electrically connected to the left hand wheel which contacts the negative rail.

Another view of the pickup block before being pressed gently home.

And the same shot with the plastic block correctly seated.

The flash exaggerates the amount of grease used. The idler gears are inserted first, and the wheels placed afterwards. Take care to gently press the pickup behind the face of the axle, and make sure that the wheel has its insulated bush on the side with the pickup. The bush can be seen as black plastic between the inner face of the wheel and the brass axle bush.

 A close up. I hadn't noticed this before - but the chewed up marks on the black axle bush on the wheel on the right of the photo confirms my suspicions about the previous owner. Why woul you want to grip that with pliers ? Thus wheel was jammed - the wheels had been pushed together so that the bush was binding against the frame.

Another pickup.  The pantographs are screwed from underneath and insulated from the body with a small red bush.  Contact is made with the two upwardly sprung copper tabs at either end of the upper circuit board, just behind the connector for the light bulb which springs down from the other side of the board.

Maintaining Classic UK Minitrix Locos
The Minitrix trademark is currently owned by Märklin Inc.  Gebr. Märklin & Cie. GmbH, Stuttgarter Straβe 55-57, D-73033 Göppingen, Baden-Württemberg

Website ©2002-2018