General Motors EMD F7A Mount Newman Mining Company

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EMD F7, picture 1


  • Roof fans driven by a micromotor
  • Swing-away access ladders on the carbody

After I got my hands on some 9V LEGO Train material, I decided to design my own locomotive. It took some iterations until I came up with a model that I liked. The result can be seen here on these pictures. I always preferred the US type locomotives over the European ones because of their usually very colorful and assymetric design. While with most European locomotives, everything has to be built twice, once for the front and once for the rear end, US locomotives usually are designed to have a preferred direction of travel and thus only one operators stand.

EMD F7, picture 2

From a design point of view, the General Motors Electro-Motive Divisions (EMD) F7 Diesel-electric locomotive represents the beginning of the new era that followed the steam age. Many subsequent Diesel-electric locomotives featured the same design language. So it was clear to me that I wanted to build an F7. After LEGO released with the set number 10020 a model of a F7 in the colors of Santa Fe I knew I could do that as well - but with some improvements over the official set.

EMD F7, picture 3

The first challenge was to find a prototype that I could convert into a LEGO model. Basically I had to find a color scheme that could be built using LEGOs standard color palette. I already had some ideas how to realize some of the details of the locomotive. Thus the choice was somewhat limited. In Australia I finally found what I was looking for.

EMD F7, picture 4

Mount Newman Mining Co Pty Ltd operates a large open pit iron ore mine in Australias Pilbara region. To haul the ore from the inland mine to the seaport, a railroad has been built crossing the Australian desert. To build this line, two used F7A units have been brought in. They were built in 1951 in the USA and first been operated by Western Pacific Railroad Company. Once in Australia they have been repainted to a bright red and yellow color scheme and numbered 5450 and 5451. I built the former one. 5450 has been in service until 1971 and then been donated to the Pilbara Railways Historical Society museum where it still can be admired today.

EMD F7, picture 5

My model is eight studs wide as in contrast to official LEGO sets that only have six studs. The bigger scale allows to accommodate more details, especially for the trucks. Thus the F7 is equipped with custom made side covers for the trucks of which the rear one is powered by a 9V train motor. It would be possible to update the locomotive with a second train motor if additional power is needed. A micromotor drives five roof fans on the carbody. It is powered via the power port of the train motor.
Most of the details that can be found on the real 5450 can be found on my model as well. These include the grilles on the upper half of the carbodys side walls, the arrangement of the headlights, the handles for the two access doors per side as well as the handles for the switching podest, the horns on the roof and many more.

EMD F7, picture 6

A major issue with LEGO trains is negotiating curves. The curve radius of the official LEGO rails is very small compared to the track gage. Thus locomotives have to be designed in a way that allows the trucks to swing out much more than it would be the case in reality. Unfortunately this fact makes it very difficult to install fixed components on the locomotives frame that protrude in the trucks area. These components include access ladders for the engineer. So far there were two ways to solve this problem. Either the ladders are fixed to the truck and thus swing sideways with them or one is doing without them.
I found a new solution - swing-away ladders. They are fixed to the locomotives frame or carbody but can give way when the trucks have to swing out during negotiating curves. The part I used for this solution has been designed as a window frame. But with its horizontal bracing it makes for a nice two-step ladder. The window frame is just hung from a hinge part that protrudes the carbody by a bit more than half a stud. Another major advantage is that these parts are available in many colors and look much more realistic than the official ladder parts that have too many steps for a model of that scale.

Finally some self made stickers with the mining companys logo and the locomotive number as well as a thin black stripe on the roof give the model a more accurate look. At the begin I planned to also build cars to go with the locomotive. But I could not find any pictures of the construction train waggons that went with the 5450. Thus the F7 resulted in a standalone model.

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