The pic below shows the modification to the air tank.



Another detail I added was the battery box vent holes. These are located on the inside of both ends near the top. There are 7 holes on each end.



I made a small jig out of styrene, marked the locations and drilled out the holes using a #74 drill. I placed the jig at the top of the box and used my #76 to drill out the holes.

After drilling out the vent holes on the battery box, I sanded smooth the battery box and the air tank joints with 400 grit sandpaper. When the box and tanks are cleaned up, I set the air tanks in place on the frame making sure the long side of the air tanks are to the rear of the frame.

I added quite a bit of detail work to the underframe, you’ll find I did allot of eye balling for these details. One thing that was important for this part of the project was to prepare all the added details like bending wire and sizing it up to be tweaked in for final assembly. Holes needed to be drilled in the frame for some of these to be cemented in place. So preparation was important along with test fitting. I did one side at a time when it came to the final assembly and tweaking. Referencing photos was very important for the next part.

First thing to do was to add the air piping and make the cooling coils. Honestly, adding the cooling coils isn’t something that can be seen on the model unless it’s upside down. The lines for the air tanks can be seen and was defiantly a detail I wasn’t going to skip. As for the cooling coils, I just wanted to add that detail.

So my thoughts turned too how I was going to add those cooling coils. I already had Precision Scale cooling coils #31162 in my arsenal of parts. These are 9ft long which are actually too short for the project. The length I estimated on the model needed to be about 11ft for the rear coil and 12ft for the front coil to look like the prototype. My solution to the short lengths was actually a simple one; I split the coils and hid that split under the bolster pads. I also removed 2 unwanted pieces of piping which will be replaced with new lines coming off the air tanks. These were cut flush to the bracket.



I sanded the bottoms of the coils so they lay flat for gluing. When I set up the coils to their proper length on the frame, I used liquid cement which gave me the opportunity to make any final adjustments before drying. I then dabbed some thin CA along the inner lines of the coils for added strength.

For this next segment, there’s allot of detailing going on. I’m going to explain the process the best I can and end it with pictures tying it all together.

Piping up the air tanks to the cooling coils was next. I have no measurements for these pipes and relied solely on the pictures I had. I made all the bends and angles to look right according to the pictures. I would test fit and tweak each pipe for the final fit which was a little time consuming, but well worth the effort.

I bent the pipes with .019 brass rod. I did the front pipes first and matched them up to the coil. After all the bending, tweaking and test fitting, I glued them in place with medium CA. I repeated the process for the rear pipes to the coil in the same fashion.
With the air piping complete, I made the sand lines that run parallel to the frame. The front sand lines run from the sand box to the back of the front truck. Keep in mind I’m doing the S1s with 4 sand lines to each truck. I drilled holes into the front of the frame where the sand lines will be glued in. I made a mark on the frame rail with both trucks in place to help determine the length. After removing the trucks from the frame, I bent the lines with .015 brass rod to shape and a length that matches up to the back of the front truck. I made these longer to hang down from the frame rail by about a scale foot.




The rear sand lines were easier to do. After eye balling a spot to drill and mount the lines, I bent those pieces and made sure they were oversized also, and then glued all lines in place with medium CA. When the sand lines dried, I set the trucks in place to trim the lines and check for clearance. I didn’t want the ends of the lines to hang down to far as to interfere with the truck swing, but just below the frame rail.

Next thing on my list was to make the drain pipes. I used a globe valve and a ball valve from Cal-Scale assortment #314. The globe valve sticks out the firemen side in front of the battery box. I added length to the valve by soldering a section of .032 brass rod to it. I drilled a #67 hole in the frame for the drain line. The drain line is mounted about center of the air tank just in front of the air pipe. I judged my length of the line according to the pictures I seen and bent the line to fit in the hole and glued it in place with CA.

For the ball valve, I drilled a #67 hole into the frame rail on the fireman side just above the back wheel of the front truck.

Final detailing of the frame involved miscellaneous air pipes along the frame rail. There were other details I wanted to add but I made the decision enough was enough.

I did need to replace the stock chain guides. They were just flat plastic with way oversized chain hanging off them and attached to the rear truck brake cylinders. There was no way I was going to add those back on with the direction I took with the frame.