Diesel-Electric Locomotive

- Image 1 - Prototype Photo This is actually the prototype locomotive manufacturer's publicity photo published many years ago. But this is also the paint scheme I am using. - Here is a short video of the first run... We got word that Jim Murray, owner of MDM Locomotive Works passed away on May 6th. The body of this F7 was a kit from MDM and very likely the the last one sold by Jim Murray. There is no word of what will become of the company. - Image 2 - My F7 before Paint And this is an actual photo of the 1/8th scale EMD F7A that I built prior to painting it. The "kit" consists of a pile of aluminum and sheet steel and a bunch of drawings with a note that says "good luck". There was also some pre-made items and a couple boxes of loose parts. The battery box, fuel tank, exhaust stacks, and pilot come pre-built. Castings include the "A" end (cab), the "B" end (wall) and steps, anticlimbers, the number boxes, stirrup steps, sand hatches, fan grilles, roof braces, hatch braces, and a buffer block. You also get six stamped and formed radiator grilles, side grille plates, tank skirt stock, and roof and hatch sheets that are rolled and formed (more or less) to the approximate shape. But the rest is totally up to the builder. To complete one of these requires machining and a huge amount of hard work. To the credit of MDM locomotive and Jim Murray, if you have one of these and have done a good job building and painting it, you will only get massively favorable comments. Everyone who has seen it in person was totally amazed. - Image 3 - F7A Floor The frame consist of twin I beams and the floor is 1/8" sheet steel. The bolster plates are welded across the I beams. The coupler brackets are welded to each end of the frame box. Here the assembly has been painted primer white.


The electronics and trucks you see in this article were not supplied by MDM. Truck castings came from Tom Bee. Drive hardware and all electronics were supplied by me. I made other modifications from the original kit plans too. - Image 4 - Fan Cover Variation For example: The radiator fan hatches have 3 braces. One at each end, and one in the center. These support the fan mounting plate. The kit instructions say to cut out 6 notches in the hatch cover to clear the braces. Not me. I milled reliefs in the ends of the 3 braces to clear the tabs in the hatch covers. It's easier, neater, and looks better. The braces already need to be machined. So what's one extra step? - Image 5 - Pilot Mounting Deviation Here's another modification I made. The kit instructions say to mount the pilot to the coupler pocket supports using two brackets provided. They also provide material to make braces to stiffen the assembly up. That's a lot of work in a mostly inaccessible area. Additionally, the coupler pocket mount is not the most robust structure either. So instead, I mounted the pilot to the floor using these four large standoffs. Easy, rugged, done. - Image 6 - Vinyl Kick Plates Kick plate material is supplied by the kit manufacturer in the form of stainless steel shim stock. These have to be cut out precisely and adhered to the body with epoxy. That's a lot of work and it's hard to make it look right. So I just ordered them in cut silver vinyl and put them on. - Image 7 - Nose Herald While on the subject of vinyl, I waited over a month to get this nose herald. I requested a quote from a vinyl supplier that I normally use. I got no reply. So I tried another vendor. After two weeks waiting it arrived with the colors backwards. So I went back to the original supplier, paid too much, but finally got it. Vinyl Suppliers Kick Plates: Speedesigns Nose Herald: Words Anywhere Side Lettering: Words Anywhere Number Boards: DIY Lettering No. The wings and stripes are NOT vinyl. Those were all painted on.

Chassis Lighting

- Image 8 - Headlight Mounting The two head lamps are mounted on a plate in the nose of the F7. They are tungsten halogen - 55 watts each. This mounting method and choice of lamps requires replacing the acrylic lens material supplied with borosilcate glass. - Image 9 - Number Board Lighting The number boards each use 3 "bullet" instrument lamps. You can see them here inside the lamp box with one of the number boards removed. This also is a deviation from kit recommendations. My lamp boxes are half the size of those in the drawings. The classification lights are simple push-in plastic lamps. This too is a modification. However, the lamp mounts are pretty much per the drawing. - Image 10 - Number Board Lamp Boxes From inside the nose, the number board lamps can't be seen. They are under that copper strip which is held to the lamp box with nylon (insulating) bolts. The under side of the copper strip is tinned (with solder) where it contacts the 3 lamps to give the lamps a good electrical contact. - Image 11 - Number Boards - Lit A view of the number boards in operation. The "kit" comes with opaque white acrylic to use for number boards with the intention of applying the numbers to the outside. Instead I used clear polycarbonate and ordered black cut vinyl numbers with a negative or reverse weed. The vinyl was applied to the inside. Thin white acetal sheet was applied over that to act as a diffuser. - Image 12 - Classification Lights A view of the classification lights in operation. - Image 13 - Pilot and Paint Can Here's a quick photo showing the nose door, pilot and front coupler in front of that paint can. Page 2