Building an OTM Tracker from scratch

 The OTM (On Track Maintenance) tracker is manufactured by Brandt in Canada.

 

 

 

 

 

 

(Photos for reference only)

Although they use John Deere components for their MOW equipments, I started with a Kibri Liebherr Excavator model.

The OTM tracker can move on top of railway gondolas and deliver track ties, ballast and rail along the railroad track, where needed. It is quickly transitioned from the highway transport deck to the top of rail maintenance cars within minutes.

Actually there is only one H0 model available, but it proves to be too expensive to ship over to Europe. So I decided to scratch build a more or less believeable representation of such a piece of equipment.

As with every scratchbuilding project, it all starts with a handful of styrene strip and profiles from Evergreen.

First, I started with the moveable frame.

I cut two pieces of #284 H-column, nine feet long, and five pieces of #175 five feet long. I then glued the five .100x.100 square strips between both H-columns, spaced like in the picture below.

Then I cut two strips of #145 to fit diagonally between the center and the outside braces. I sanded and beveled the strip, until they fit correctly. (see picture below)

Next, I modeled the ends of the frame with the hydraulic pistons (simplified)

I need two pieces each of #266 channel and #138 square strip, cut to seven feet length. One square piece is glued to the back of one channel piece. Then I cut four #223 tube two feet long. These are the pistons and glued to the outside edges of the channel assembly. (picture below)

Then I glued the piston assembly to the edge of the frame, like in the above picture with the completed frame.

The next sub-assembly is the moveable pads, which rest on the rim of the gondola.

I cut two #252 square tube pieces 8.5' long (they should loosely fit between the gondola walls).

Then I cut four #153 square strip pieces four feet long and also four #133 strips, one foot long. The small strips are glued to the edge of the square strip, to form the pad.

 

Unfortunately the pads fit very loosely into the tube, so I carved the shaft with my hobby knife, to give them more friction inside the tube. Care must be taken  not to cut or brake the shaft. I know it's not the most elegant solution, but it works. Probably after painting the shafts, there will be some friction also.

Then the pad assembly is glued to the bottom of the frame, like in the picture below. I added round styrene strip for the pistons. I have a sample pack from Slaters, so I don't know the exact size, but 1/32" should fit.

The frame assembly should look like pictured below.

Now on to the lower frame of the tracker platform.

We need two #252 square tube pieces again, and four each #153 and #133 of the same dimensions than for the large frame.

The two #284 H-column pieces are 7 feet in length. They are spaced with two #155 strips of 6.5 feet length. The two pad assemblies are glued to the edges of the #155 strips. 

Two #133 strips are glued crosswise to the square assembly. It will look like on the picture below.

The lower platform and the large frame will look like in the following photo, with the large frame resting on the lower platform. They should barely touch.

As I mentioned above, I did use a Kibri kit #11264 instead of the prototype John Deere Excavator.

For the upper platform, to which excavator is mounted to, I used the chassis from the kit and assembled the part following the instructions. It's only a two-part assembly. The axle suspension will hold the hydraulic pistons. To do this, I cut the lugs, which usually hold the axles, and sanded the underside flat, like seen on the picture below.

I cut two pieces of #175 square strip 6.5 feet long and glued #223 tube pieces at each end of the strip. These represent the four pistons.

Then I glued the two assemblies to the axle mounts on the chassis, like seen in the picture below.

The length of the 'pistons' should be at least match the thickness of the large frame H-columns.

The upper chassis and the lower platform are now glued together with the large frame sandwiched in between. The large frame should move freely between the chassis assembly. Styrene rod is inserted into the round tubes to simulate the pistons.

Now the assembly is ready for the paint booth.

My OTM tracker painted and weathered.

A nice piece of equipment added to my modern fleet.

Next up will be another OTM tracker with a Caterpillar Excavator. 

Stay tuned and thank you for your interest. Comments always welcome.

Building a cheap electric static grass applicator

Standing grass is a very realistic scenic feature on every train layout or diorama. Unless you are really building large layouts professionally, you don't need one of these expensive tools which quickly cost in the 100 Euro range. That's my opinion and the bucks saved can be invested into more models. So, if you want to know how to save money without missing the opportunity of having good looking grass on your layout, keep on reading. I'll show you in a couple of steps how to do it.

There are multiple designs of electric fly swatters, so it doesn't matter which one you choose. The blade will be removed anyway. The electronics inside is always the same. Look for a model where the two halves are screwed together. Otherwise you will destroy the handle.

 

 

The fly-swatter consists of a handle to which the swatter is attached with a couple of screws. When unscrewing the two halves the swatter may be detached from the handle. A small electronic board provides the high voltage needed. I detached the two wires and discarded the swatter.

The biggest problem consisted in finding a plastic sieve with a metal mesh. Any other metal sieve would also work, but then the danger of accidentally touching the sieve and getting an electric shock would be higher.

I shortened and drilled two holes in the handle to fit over the two pins that held the swatter before. This could be different, depending on what swatter you have. A bit of improvisation is advisable. 

 

 I soldered one of the wires to the mesh.

 

 

 

Then I lengthened the other lead with a clamp on one end. This is the ground wire, which will be clamped to a screw or nail inserted into the scenery.

To avoid using batteries, I soldered two wires to the battery contacts to power the unit with a external power pack.

I bought a 3V / 1 Amp power supply for less than 3 Euros and connected it to the wire using a male and female plug.

My power cord is about 2 meters long, which is enough to move around freely.

I attach the ground clamp to a screw, inserted in the center of my workspace, where I want to plant my static grass.

The advantage over an applicator with a pot is that you may reach lower areas easily.

Nevertheless I could not resist to buy one of the cheaper offerings with a large pot and two different styles of mesh. This one makes applying longer static grass easier. Next I will change it to external power also.

The small sieve is ideal for the short 2mm fibers

Here is an example of static grass applied to seaweed for bushes and in tree making.

 

My first attempts with static grass application.

DISCLAIMER: Be aware that this electric device may cause an electric shock. If you build it, you use it under your own responsibility.

Athearn Boxcar improvement

Despite the many beautiful ready-to-run rolling stock available nowadays, I am still a big fan of the old Athearn Blue Box and Roundhouse (Model Die Casting) kits. Many can still be found unbuild, but at swap meets or from various Facebook Sales Pages, some are already built and more or less refined.

Recently I happened to acquire a 50' boxcar, among others, which was already assembled and upgraded with Kadee couplers and metal wheelsets, probably from Intermountain.

The car had been assembled following the instructions with the horn hook couplers replaced with Kadee's and the original wheelsets with better running metal sets. I must admit, on this car the metal coupler pocket clips had been mounted correctly. I simply hate them, because, for whatever reason, I never managed to get them on straight. After a while, the clip always fell off or the coupler did not sit correctly and drooped. 

Anyway, I disassembled the car into its basic components, which are only a few (body, floor, underframe, weight, and trucks)

With a small screwdriver, I unclamped the metal clip and the coupler came loose.

These early kits always have a lot of flash from the molding process, which prevents the parts from fitting flush. This was the case here with the underframe. A few passes with a sanding stick is a quick remedy to this.

Next, the coupler pockets had to go. This is quite easy using a razor saw.

Another step I always do on boxcars, turning the floor. Normally the boarded side goes up into the body. On boxcars with opening doors, this might be a nice detail, but as the boxcars usually run with doors closed, this isn't visible either. On the 50 footers I bought, the doors cannot be opened. By turning the boarded side down, the floor really looks like the real thing, because that's what you normally see from underneath. I simply screw the underframe to the turned floor and for a permanent fix, I also glue the frame to it.

Then I glue the lid of the Kadee draft gearbox to the floor, taking care to center it. After the glue has set, using the center hole as a guide, I drill and tap for a 2-56 screw.

Then I assemble the draft gear box and secure it with a screw.
 

I attached the metal weight to the floor using double-sided tape. This is no permanent fix, believe me. A small piece of leftover styrene, drilled to fit over the "original" bolster pin and then secured with a few drops of cement will keep the weight in place.

I will never open this car again, so I glued the floor assembly to the body. The clamps make sure that the bond will be permanent.

A final detail, which is quickly added consists of replacing the oversized steps. I simply snapped the original steps off using a small sprue cutter. Don't bother to drill into the sides! Chances are that your drill slips. I drilled immediately behind the side, next to the floor and inserted A-Line wire steps. These are not only smaller, but also sturdy.

Remember, this is not a contest model. My primary goal is to have a reliable car intended for operation. Nevertheless, some of these tips may also be a base for a better-looking model.

Stay tuned. In a future installment, I'll show you a quick weathering technique.