The next step is to installed the chassis to the body. It is important to have the trucks' sideframes connected to the trucks, because of clearance issues; it helps to center the chassis in the correct location. This photo shows the chassis positioned in the body, and the chassis mounting brackets shown above and below the model. Note that the kit comes with 6 mounting brackets, four long ones and two short ones. The two short ones are used for installing the chassis to the body (the four long ones are used to connect the body to a chassis other than the one sold by Railmaster Hobbies).

However, before mounting the brackets, the rear screws must be installed first. Make sure to position the chassis exactly where you want it. This is where the side frames being attached to the trucks is important, because you can make sure the trucks clear the pilot step assembly when they swivel. The close-up photo below shows where the pre-drilled hole in the chassis lines up over the mounting tab of the walkway. This provides additional material into which to drill the screw. My kit did not come with screws for mounting the chassis to the body. It would have been a big time-saver if the chassis kit would come with those mounting screws. I had to dig through my collection and eventually found two self-tapping screws that fit the pre-drilled hole.

With a pencil I marked where the holes needed to be drilled in the walkway underside.

I then installed the screws. When I then started looking at installing the mounting brackets on the front end of the chassis, I noticed that they didn't fit. They were too far away from the underside of the walkway. When I examined to see what was causing this, I noticed that the screws used to mount the truck towers to the sheet metal of the chassis were sticking out and hitting the underside of the walkway. I looked at the engine from a side-profile and noticed that the chassis' sheet metal was clearly visible. According to the instructions, the chassis plate is supposed to fit up against the underside of the walkway.

This is a close-up of the problem. The screw sticks up above the chassis sheet metal.

To solve this problem, I simply reversed the truck tower mount. The screw mounts into the metal bracket that connects to the tower, so it has to be reversed. That way the screw sticks out under the frame where it won't interfere with anything. This makes the trucks sit slightly lower than before, but the drive mechanism of the chassis has universal joints, so it can handle the positional change.

With this change made, the front mounting brackets fit perfectly, and I was able to glue them into place. The instructions tell you to remove the chassis to mount the brackets, but I wasn't about to risk not quite getting the brackets' location right and not being able to fit the chassis in later. I left the chassis in place, then simply inserted the brackets, with 5-minute epoxy applied to their underside, under the chassis.

The North Yard chassis is a simple sheet of metal with two trucks mounted to it. However, it becomes the foundation for attaching underbody details. These are the battery box, the fuel tank, and the girder. This photo shows the three parts that make up each sub-assembly on the right, and the parts in their approximate position on the left. Note the orientation of the fuel tank (the oval-shaped part). It must be toward the cab (short end) of the engine. The parts, once installed, must be directly opposite of each other, so when you assemble them to the girder, they must be assembled in mirror image, as shown in the photo. Two notes here: first, make sure the back side of the girder is truly flat and straight before gluing the two parts to it (I forgot to do that and had a bit of a challenge getting it straight afterwards); second, be sure to check that the perpendicular mounting bar on the back of the girder is at a 90-degree angle to the back of the girder, because that will be glued to the underside of the chassis later and the girder needs to sit perpendicular to the chassis.

I studied prototype photos to determine where the fuel tank is supposed to sit to determine where to install the fuel-tank-battery-box-girder sub-assembly. The girder's 90-degree mounting bracket comes with a dimple in it and presumably that lines up with the pre-drilled hole in the chassis, but I decided to make sure to position the sub-assembly correctly using 5-minute epoxy only first (I will come back and re-enforce this with a screw later on). This photo shows two metal weights I used to just fit in between the two sub-assemblies to hold them down while the glue set. The front edge of the fuel tank is supposed to be flush with the edge of the walkway above it. My prototype photos show the battery box to be flush with the walkway, but I'm willing to let that slide.