Three railing a Bachmann 2 EPB

I fancied a blue EPB and after the recent success with the other Bachmann units I decided to make another purchase.

This one is second-hand, which doesn't bother me, actually I prefer this because of what I'm about to do to it!!!

It's often said that the best things to run on three rail track are proper three rail locos that were designed for that purpose. For successful conversions I've found that you need four key things:

1. Weight (to compensate for the resistance from the third rail skate)

2. A decent, secure method of collecting power from the centre rail

3. Sufficient clearance underneath to mount a pickup

4. Current return to as many wheels as possible

This is where I've found the Bachmann EMUs to be the most successful. The motor carriage is nice and heavy, it can cope with the added resistance from the pickup assembly whereas my attempts with Tri*ng DMUs were less successful due to their light weight and awful wheel flanges.

What follows in this post is the process I used to convert my EPB to three rail running. I'm not an expert, this isn't a how-to guide - if you choose to follow this and trash your beloved possessions, don't blame me!

So here's my shiny new (to me) EPB motor coach...

And here it is in the nude with it's body carefully prised off.

Both bogies are removed as I need to modify both of them.

This is where the power is collected from the non-powered bogie, the contacts brush against the copper terminals that protrude in the picture above. I need to remove the power collection from one side as this will become the centre pickup.

I need current return to all the wheels, I also need to ensure that power collector is isolated on the same side as the non-powered end.

One of these is about to be removed.

This is the power collection at the motor end. It is possible to bend these out of the way rather than cutting the strips but as I have no intention of ever returning to two rail operation, I can be more brutal.

And this is where forming the new centre pickup begins.

A piece of vero board (it has many names, peg board, bread board, PCB project board etc)

The beauty of the vero board is that all those pre-drilled holes mean no extra drilling!

The strip is cut to size and lines up perfectly over the existing pickup screw holes.

I will need to remove the existing pickup retaining screws and replace with longer ones that I sourced ages ago.

Easy way to establish current return on the powered bogie. A paper fastener, which can also be used for the centre pickup, is cut and the strip bent to the shape of the underside of the bogie, it is then pushed under the existing collector strip on both sides.

This may look like a total bodge, but it avoids the need to solder wires and this method was used on my first Bachmann three years ago as a temporary fix. It's still there and you can't see it unless you look underneath!

If the strip doesn't stay in place then it is possible to carefully solder it at each end. A powerful soldering iron with a small tip is recommended and be quick, there's plastic everywhere.

Now that I've worked out which side to take the centre power from, I cut off the connecting strip and fed a wire through the gap. Thin, stranded wire, smaller the better is crucial here. If the wire is too thick or too stiff it will affect the movement of the bogie and the unit will derail on every corner.

The Märklin skates have only one small centre fixing, which from experience isn't enough for this kind of application. I screwed the pickup into position using one of the chassis screws temporarily just to centre it, the skate is then soldered on each side and the wire soldered to it. This is going nowhere and the centre screw is then removed. 

The pickup is now perfectly centred - this is essential for good running over points, crossovers and tight corners. If the pickup isn't dead-centred then there is a risk of short-circuiting or stalling over points.

Finally and using longer screws, the new pickup assembly is screwed over the top of the existing ones. This is all done with the bogie screwed back into position on the chassis. Should the bogie need to come off in future, it's just a matter of undoing the two screws to access the centre screw underneath.

What can't be seen here is another wire soldered underneath between the two existing pickups to give me current return to each side.

The wire from the new pickup is soldered onto the pcb above, with sufficient slack allowed for the movement of the bogie.

With the wheel continuity tested, the body is refitted and the unit tested.

Testing the lights...

No modifications have been made to the trailer coach, the whole unit lights up correctly, but only when running forward. For me this is fine as I don't run in reverse. When reversed the rear coach lights go out. To solve this a second pickup would be required in the trailer coach and ballast as the un-powered coach is so much lighter. Again for my purposes this is not necessary.

The final modification for it to run with the other EMUs is to fit Kadee couplings.

This unit had no couplings fitted at all and these simply push-fit into position. The metal bar is then bent upwards to clear the centre rail.

And here are two EPB units coupled together.

All finished in under an hour. Minimal tools and materials needed.

This job can be done in exactly the same way using brass paper fasteners as a collector but I found that these are more fragile, require regular adjustment, create more upward resistance and tend to squeak and squeal againts the centre rail. The Märklin skate is a much neater and more sturdy solution and are readily available brand new. They also clean up the centre rail a treat!