The control tower project 2

The control tower project

Organizing digital components — Part 2

By Ernest H. Robl

This is the second part of an article that was split into two parts because of its length. This part describes how I built the booster rack and how I arranged the components in it. If you have not already done so, please look at Part 1 first. That way, what follows will make more sense.


Once I concluded that I needed a rack for the boosters and associated accessories, I began looking at some of the factors that would affect construction.

My first thought was to build the rack so that it could later be mounted to the underside of the layout surface. But, two factors dissuade me from that:

  • With some older MRC utility transformers (one of which would be used for analog control of switches in the main station), the rack was likely to be relatively heavy, requiring strong benchwork in that area, or at least some special adaptation of the benchwork.
  • With the rack permanently mounted to the layout, access to the underside of a key part of the layout would be difficult. With the rack on the floor and sufficient slack in the layout feeder cables, I could at least move it a short distance from side to side to gain access below the top of the layout.

As most of the components that I planned to put into the rack, such as the boosters and network hub, were relatively light, most of the intermediate shelves could be thin. That led me to use thin tempered fiberboard, which I had used for control panels and other parts of my previous layout. This fiberboard comes in 4×4 foot sheets.

To help keep the components on the shelves in place, I decided to use the fiberboard the with rough (patterned) side up.


A side view of the booster rack, showing the heavy-duty power strip with power switch, overload protection, and surge protection.

Power supply

Cable management was a concern from the beginning, and that included line power to the various power supplies and transformers.

I already had several heavy-duty power strips left over from the days when I would sometimes need to set up substantial artificial lighting for location photography. I chose a power strip with all of the following features:

  • A power switch for all outlets
  • Surge protection for the items plugged into the outlets
  • A circuit breaker for overload protection.


The top of the booster rack with the two hand-held Multimaus control units. Temporarily sitting on top of the rack is a Roco Route Control, which, like the Multimaus units, is connected to the Multizentrale amplifier.


And, a back view of the same area showing the booster network hub.

Cable management

While cables that are too long can always be bundled up, the weight of the excess cable adds extra strain on the connectors – and this doesn’t look very neat. So, the most logical approach is to use cables that are just the right length.

When I bought the network hub from the small manufacturer (Moba-Technik) in Germany, I noticed that he also offered various lengths of all three types of cables used in the Roco Multimaus based system:

  • Cables between the Multimaus controllers and the main amplifier
  • Cables between the amplifier and the boosters (or between the booster hub and boosters)
  • Cables from the amplifier and booster to the tracks (or digitally controlled devices), the so-called track feeder cables

So, I purchased some of each of those in various lengths. Several of these were shorter than the ones offered by Roco, of which I already had ones that came with the various components.

Important: Though some of the cables used to connect various DCC components, both in the Roco system and in systems of other manufacturers, may look like telephone cables, they are not! Telephone cables may have different (cross-over) pin wiring – in other words, the wire on pin 3 on one end is connected to pin 2 on the other end – and/or may not have all the requisite pins on the connectors wired up.Why is this important? Because in some digital cables, one pair of wires carries 12-18 volt power to a component while another pair carries low voltage digital signals. Supply the wrong voltage to the wrong pin connector on a device, and you have fried that device.Yes, you can make your own DCC network cables of various lengths – if you have the requisite connectors and crimping tools to assemble those connectors and you know what you are doing. (That may require research on the wiring standards for various cables – and double checking all pin connection on the assembled cables before attaching them to anything.)

Barring that, it’s best to stick with cables supplied by the various manufacturers and third party vendors who know the appropriate standards.

Whatever you do, DO NOT use standard modular telephone cords.

The Roco 10853 switch mode power supplies came with detachable EIA line cords that were about four feet long. (EIA – Electronic Industry Association – cords are ones with a standard triangular connector on one end, also used for computers and other electronic devices.)

I thought I could do better by getting EIA cords that were only a foot long. But, these turned out to be too short. My solution was to add a three-way connector and a one-foot extension cord. You can see that in the rear view photo of the tower. Not the most elegant solution.

If I add other Roco 10853 power supplies, I will probably just stick with their four-foot cords. (There may be two-foot EIA cords available, but at this point, it’s probably not worth looking for and purchasing them.)


Okay, how did I select the dimensions of the tower and its components?

Well, in part the sizes of the shelf openings were determined by the size of the components I planned to put into them.

All electronic components generate some heat, and air flow is important to their safe operation. So, I did not want the spaces around them to be too confining.

The final width of the shelf openings – six inches – was determined by the space needed for two Roco 10853 switch mode power supplies side by side.

The vertical openings were based on the height of the components – and the fact that I already had some wood pieces with 1×2, 1×3, and 1×4 dimensions. (I did end up purchasing some additional wood, including a piece of 1×6 wood.

The 1×2, 1×3 and 1×4 pieces were cut to six-inch lengths and used as spacers between the shelves.


The entire assembly was put together with drywall screws. Though these are self-tapping, I did drill pilot holes and countersunk the heads to avoid splitting the small wood pieces.

After first assembling the box area at the bottom of the tower – trying to keep everything as square as possible with special corner clamps – the rest of the shelves were assembled as inverted U pieces.

In other words, I selected the appropriate 1x-spacer pieces, put a piece of fiberboard on top, and then screwed that fiberboard to the spacers. These pieces were simply temporarily stacked one on top of another.

This stack was then measured for the length of the side rails that were screwed on to hold the entire stack together. One of those side rails holds the main power strip.

Two 1x3x8 pieces were selected as parking spots for Multimaus controllers. (These have a keyhole opening on the back, allowing them to be hung on a small screw.)

I spray painted the subassemblies with dark gray paint before final assembly – and then gave the assembled tower another spray to touch up some of the pieces.

The contents

Here are the current contents of my booster rack:

Roco 10830 Multizentrale Pro
Moba-Technik booster hub
Roco 10765 booster
Fleischmann680801 as booster
Roco 10764 as booster
2x Roco 10853 power supply
MRC MH800 utility transformer
MRC MH800 utility transformer


In the illustrations with this article, you will notice that I am using both Roco and Fleischmann digital components. The digital components of the current systems of these two brands are functionally identical, and fully compatible. Only the labels and colors of the items are different.


Rear view of the booster rack, showing some of the cables connecting the components. None of the track feeder cables have been connected yet.

Note that the second Multimaus controller – the gray one with the Fleischmann logo – is set up in such a way that it can be unplugged and later plugged into network sockets to be located in other parts of the layout.


Let me know if the above material was of interest and provided useful information. I realize that advanced modelers (or those more skilled in woodworking) may not find much new in the preceding two-part article.

But, for me, figuring out how to do something is often more fun than the actual implementation. I did learn something along the way – and I hope it helps others.

Did I provide enough detail or too much detail?

While you can add comments at the ends of these Blog postings – and they are certainly welcome – for a more extensive discussion, you may want to go to the Digital section of the Reynauld’s Forum.


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