CNR 3737 :: Snow melter fittings

CNR 3737 - Prototype Photo

I’ve been thinking about the snow melter equipment on my CNR 2-8-2 project ever since I installed the big wrapped pipe for it last week. I know that this pipe supplied steam to equipment that melted the snow and ice out of switches in yards. But beyond that, the photo of 3737 that inspired this build (shown above) doesn’t really make the fittings clear to me.

So, I did some research with the aid of Canadian National Steam! – the the excellent series of books by Donald R. McQueen, published a few years ago. In one of these, I found a photo of CNR 2-10-2 4033 with a much clearer photo of the snow melting equipment – a portion of which is shown here:

CNR 4033 snow melter detail

I’ve highlighted three important points with white arrows. First, there’s are two shut off valves on this pipe – one near each end of the pipe. Second, the front end of the pipe appears to be fitted with the same sort of steam line connection that’s used on passenger cars for steam heating.

With this information, I look another look at my subject photo and things became more clear:

CNR 3737 snow melter (detail)

First, now that I know what to look for, it’s easy to spot the wheel on the shut off valve just ahead of the steam dome. And while I cannot see the second shut off valve, at the front end of the pipe, I will assume it’s there and model one accordingly. Perhaps it’s hiding behind the handrail in this photo.

Finally, while I had spotted the steam line connection back at the start of the project, I didn’t know if there was anything more to the system at this end of the pipe: now, I know that this is all I have to model.

Precision Scale offers valves in a number of pipe diameters, including ones cored for these wrapped pipes. So I’ll be placing an order for those soon. And BTS makes the passenger car steam line connectors, which will work fine for this application. I’m already building the shopping lists…

CNR 3737 :: ash pans and doors

Yesterday’s work session with my friend Andy Malette focused on the firebox of my CNR 2-8-2 project – specifically, the ash pans.

CNR 3737 ash pans and doors

The stock model has a pair of cast brass plates that run across the bottom of the firebox. These are screwed to the body of the model from underneath, as they must be removed in order for the motor slide into the firebox area. The plates project beyond the edge of the firebox but needed to be bulked up to better represent the bottom of the prototype. So I soldered some bar stock in place along the top of each plate, while they were still attached to the model – being careful to not solder them to the firebox wall. I then unscrewed the plate and shaped the bar on a bench grinder – working a little bit at a time and cooling the brass in a pot of water so that the solder would not melt and the parts separate.

Andy had prepared for the session by cutting some square tubing to create the frames for the four ash pan doors – two per side. I filed these to better fit against the curve of the base plates, soldered them in place, then returned to the grinder to finish them. A light touch was required, with regular checking to make sure I was grinding them so that their outside edge would be vertical when installed on the model. I finished these with a file.

Finally, when I was satisfied with the door frames, I made the doors themselves. These are simply pieces of styrene sheet cut to fit between the sides of the door frames, left long and soldered in place, then trimmed level with the top of the ash pan.

With these built, I test-fit the new ash pans in place. I had to gently bend some piping out of the way to get them to fit, but otherwise it went fine.

The last step was to add two blow-downs to the firebox, on the engineer’s side. These are spare castings from Andy’s CNR K3 Pacific project from a few years ago. I cut off a large discharge pipe on each. Then I drilled holes in the firebox side, soldered the castings in place, and added smaller discharge pipes that line up with the bottom of the ash pans. There’s a large hole from a removed casting that I’ll need to fill – the easiest way will be to simply solder a brass NBW casting or a piece of brass plate over it and be done with it.

There’s lots more to do, of course. But I have a busy couple of weeks ahead of me so we may not get back to the project until next month. Meantime, I’m putting together a list of details that I need to buy to continue this build.

CNR 3737 :: The big pipe, and other progress

CNR 3737 - Prototype Photo

I had some time today, so I put the phone on mute, turned off the computer, and spent the day in my basement workshop. The result is, I made a lot of progress on my CNR 2-8-2 project.

The first order of business was piping…

The big insulated (wrapped) pipe across the top of the locomotive in the prototype photo is the primary reason I picked CNR 3737 to model. This unusual feature was to deliver steam to an appliance at the front of the locomotive that was used to melt snow and ice out of yard switches in the winter. The melters themselves are not visible in the prototype photo – presumably, they were removed in the summer, and this picture was shot in August. But the steam delivery pipe is very obvious.

Months ago, my friend Andy Malette provided me with a length of wrapped pipe from his stash. I straightened it and re-bent it with pliers to approximate the path of the prototype pipe:

CNR 3737 - Snow Melter pipe

I drilled a hole in the steam dome to accept the end of the pipe, then realized that if I soldered it in place, I would never be able to remove the smokebox front. Given that there are lights to install and maintain, this seemed like a bad idea. So, I made sure the pipe was long enough to fit firmly in the steam dome hole, then soldered the pipe to the smokebox front. It now comes off with that front piece, all as a unit. As I add additional details, I will see if this will continue to work. If not, I’ll have to come up with something else.

Now, I have to do more research on the snow melters themselves. Time to go through my CNR steam books, looking at photos…

CNR 3737 - condenser pipes

While piping, I also installed the condenser coil under the running board. This runs from the air pump, behind the feed water heater pump, to the small tank under the running board. It then runs from that tank to the larger tank that’s between the front ladders, on the pilot deck. I bent up the pipe using some 0.032″ wire and mounted it to photo-etched brackets supplied by Andy – although a simple L-shaped piece of brass bar would serve if the brackets were not available.

As a bonus, the pipe to the large air tank is soldered to the short running board next to the smokebox, which helps strengthen this. It has frequently come unsoldered as I work on the locomotive – but it’s not moving now. (I’ll have to come up with a similar pipe to support the running board on the other side.)

Further back, I realized I could add the cover to the steam turret housing, just ahead of the cab. I cut some thin brass sheet to size, rolled one end around a piece of brass rod, and installed it:

CNR 3737 boxtop

Finally, I tackled a fiddly project: the seven triangles that support the cab roof smoke deflector. I cut triangles oversize, tinned them, and soldered them in place. I then ground the backs of them down to size.

CNR 3737 - 7 triangles

This was a messy process, but it worked – although even now I see triangles that need some adjustment. That’s easy enough to do with metal.

While this represents a lot of progress, the biggest step forward is something that can’t be seen in the photos: Namely, that I did this work on my own, without Andy’s guidance. The point of this project, for me, has been to learn how to do this work – and I realize I’m starting to gain the confidence to forge ahead on my own. That’s very good news, because it means I’m internalizing the skill set. I’m certainly no master – and there will be many more sessions with Andy, including one scheduled for tomorrow afternoon – but it feels great that the work is paying off…

Maybe we’ll even get our CNR S-3-a Mikados finished this year? Tonight, it feels like anything’s possible!