Märklin 1 - Altmühlhof

Altmühlhof is the name of the outdoor Märklin railway described in the 0324 book, “Märklin I für Haus + Garten”. The completed railway measures about 4 meters by over 6 meters (13 feet by 20 feet), allowing for two train operation, controlling trains with 5611 semaphore signals.  It also features an indoor storage area for the trains when they are not in use.  The name “Altmühlhof” is also used in the Märklin catalogs to describe the 5615 station kit:

Märklin personnel had a penchant for naming their station kits and other structures after existing buildings, but there is not a clear prototype for this particular kit.  Certainly they used the plans of a real station structure, but there is no “Altmühlhof” town. The only thing that is close is a group of vacation cottages located in the Middle Franconia region of Bavaria, about a 1 1/2 hour drive from Märklin’s home town of Göppingen.  So, the name may have been chosen out of sentimentality.

Regardless, the 5615 station kit is the center piece of the Altmühlhof outdoor railroad, but even they could not leave well enough along.  The station structure is actually two 5615 kits “bashed” together to form a more unique building.

Garden railways have a long tradition, with much of the early development occurring in Great Britain.  Famous for their gardens already, many Brits could not resist putting trains into their outdoor areas, and the rest is history. Although the outdoor railroad hobby dates back at least to the 1930’s, it is a relatively new phenomenon in the United States.  Much of the garden railroad hobby owes a debt of gratitude to LGB for popularizing garden railroading, but Märklin can also be considered a promoter of railroading outdoors. The Altmühlhof railroad is the best example.

To be sure, much of the techniques used to construct Altmühlhof were already well established, but there were still some pioneering efforts on this railroad. At that time, there was a limited amount of garden railroad supplies available, so this railroad has more than a little improvisation and scratch building. Although written in German, the information about the construction of Altmühlhof is still worth a look.

As with the indoor railroad Rossberg, Altmühlhof appears to have been constructed around 1980 or 1981, with the 0324 book being published in 1983, a few years later. Because the Altmühlhof article was written more than thirty years ago, the techniques are somewhat dated, reflecting the practices of that time, and earlier. You will notice that the Altmühlhof railroad has a certain bullet-proof quality from one perspective. At the same time, some of the Altmühlhof design is quite vulnerable because the Märklin switches and signals from that time were not weatherproof.  Märklin has subsequently corrected this problem, but the solenoid devices from that era were not designed with rain and snow in mind.

The track plan is a simple twisted oval, forming and over & under “figure 8”:

The town of Altmühlhof is a junction point, with a branch line curving away from town parallel to the main line and then winding off into the distance.  Note the phrase “zum Keller”; the branch line’s eventual destination is the basement of the railroad owner’s home. This provides three track storage of the trains in a secure location, yet allows for their easy introduction to the railroad display.

The Altmühlhof railroad is built with only the 5932 wide radius curves and the 5972 & 5973 large radius turnouts, so the very popular Märklin Class 38 has full run of the railroad. Of course, the smaller locomotives look better on these wide curves, too.  There are only a few structures on the railroad.  One is a kit-bashed 5615 station, a smaller building built with the leftovers and a coal stage for fueling the locomotives. The coaling station is likely to be a preproduction model, since it looks like the 5618, which was introduced in 1980.  The Altmühlhof railroad has three signals, but little emphasis is given to the controls of the railroad in the book.  It appears that the 6699 electronic controller was used, with a fixed power supply feeding both the controller and the electrical accessories.  Likewise, the traditional 7072 control box appears to have been used.

Construction of the right of way is substantial, using concrete for the base with additional layers to support the track. The central part of the Altmühlhof display is a square panel of wood that forms the junction point of the railroad. It sits in a metal frame:

By doing so, it was possible to properly fix all the track switches and signals, with all electrical wiring being placed underneath, in conduit and electrical boxes:

Construction started with the general laying of the curves and tangents that formed the railroad. Here, one of my favorite photos, where the family cat, Titus, gets involved by doing what cats always seem to do:

The German precision of that era is everywhere:

The gradients are laid out using a straight edge and clamps, string, a bubble level and a meter stick, working from a fixed elevation point (“50” on the left in the illustration).

The cement right of way is placed, using the junction trackage as the central reference point:

After the initial layer of cement, a layer of Moltofill® is applied.  Moltofill is a popular German product which is used “For repairing, filling, leveling and smoothing. For installation of gypsum boards, gypsum boards, hard foam and lightweight panels. For bonding of stucco moldings and rosettes. For shaping and modeling.”  After the Moltofill, a layer of Styropor is applied. This appears to be an insulating foam which is bound to the cement by the Molotfill.  A portion of the track is applied to this amalgam of concrete and foam.

Once the cement rights of way are placed, rocks and other scenic structures are applied:

The track is set on the cement rights of way, the metal support frame fitted and the junction segment finally applied:

After the admiring neighbors depart, installation of the plants and shrubbery continues:

The basement siding is worth considering, too. Trains exit the main line, winding downward to ground level and continuing into the basement via a drainage pipe:

The track support uses a shaped wood piece that matches the curvature of the interior of the pipe, with a track support plate on top. A wire race (“Kabelloch” in the drawing) at the bottom of the curved piece allows for wire routing.

I have used this technique on an installation, and it does work. The technique requires the cutting of several curved supports, attaching the track plate and the track, attaching the wires to the wire race, then applying construction adhesive to the bottom of the curved support pieces and inserting the assembly into the drainage pipe. Once the track support assembly is placed in the tube, a custom sized board is inserted through the length of the pipe to hold everything in place while the construction adhesive sets up.


Special wiring circuitry allows for control of the trains entering and leaving the storage area.  And, presumably, there is a door which can be closed to keep out wild animals.


I can find no record of the disposition of this railroad, but I am guessing that it is long gone.  Here, one reminder of the issues of outdoor model railroads:

Although Altmühlhof was designed so that the signals could be removed after railroad operations, the solenoids for the track switches could not. This railroad was influential, however, and a lot of outdoor railroaders adapted this design to meet their own needs.