HO Grand Trunk 2-8-0 (Class D2)

[sailormatlac]

Matt, in your diagram of the firemen's side of the locomotive, the pipe between the cab and air compressor, which you've labelled "compressor exhaust/compressor steam" is actually a steam delivery pipe, taking steam from the turret (basically a manifold for distributing steam to various small appliances, such as the air compressor, generator, etc). The exhaust for the spent steam is the line coming from the top portion of the compressor, which runs to the smokebox. On a more modern locomotive, that exhaust might be one of several leading instead to a feedwater heater - no point in wasting heat if it can be utilised elsewhere.

Make sense and fits what I see on high resolution picture and from piping diagrams.

The dotted line between the compressor and air tank won't likely go directly to the air tank, but rather through a length of pipe and/or pipe arranged as cooling coils, since the air coming from the compressor will be hot. That pipe could go behind the air reservoir or might also pass over or under the boiler. I recall reading that the air was required to pass through at least 75' of pipe before entering the reservoir tank. Those dashed lines may be a pipe from the reservoir to the brake stand, but it would be more commonly seen on the engineer's side of the cab, where the brake stand is located.

OK, I was curious if early locomotives had the coil, seems yes. The pipe connecting the air pump and tank is clear on the picture. I jusst guessed it connected directly. It looks like an elbow going under the boiler. If I understand correctly, the coil would be hidden behing/under the boiler which is logical with the care taken to hide everything on this loco.

On the lower diagram, showing the engineer's side, that dotted line labelled "where does it go?" is likely the pipe from the last air reservoir in the system to the engineer's brake stand.

OK

The pipe labelled "to tender" is actually a water line from the tender, similar to that on the fireman's side. There should also be an overflow pipe for the injector on this side.

On in service pictures, I see the overflow. On the builder photo, I don't see it. Lesson learned: builder photos are not always taken when the engine is fully completed so one must be cautious.

The small lines at the cylinder are likely lubricator lines to supply oil to the valves. Since this locomotive had Stephenson valve gear, the actual lubricator, which ran off the motion of the valve gear through a connecting rod, would be located between the frames of the locomotive, under the boiler, along with the valve gear. The lube lines likely ran from there under the sheet metal boiler sheathing, re-appearing at a point near the valves. These lines should be similar on both sides of the locomotive.

OK, so small pipes entering the jacket would do the job.

The part on the Bachmann 2-8-0, missing from your prototype, is a power reverse, which moves parts of the valve gear to control whether the loco moves forward or in reverse when the throttle is opened. On small locomotives, which often used Stephenson gear, the reverse rod or reach rod would extend from the valve gear into the cab, and would be moved manually by the engineer.

That's what I thought. On the CNoR locomotive in the post (which have a Walschaert valve, we can see a rod extending from the cab to the valve gear. I imagine it would be similar except the rod would likely be somewhat coupled with the valve under the boiler.

Hope this clears up some of the mystery.

Sure it does! Now I have to do my homework.

If you can find it, the 1925 Locomotive Cyclopedia is invaluable in explaining the intricacies of steam locomotives. The book of which I speak is actually a reprint of the original, 1131 pages offering way more than most of us will ever need (or want) to know on the subject.
Another useful volume is Model Railroader's Cyclopedia - Volume 1 Steam Locomotives. It explains, with photos and diagrams, many of the features common to steam locomotives, and does so in simpler terms. There are lots of photos and diagrams in both books. I found both, used, at two different train shows.

I absolutely need reference books indeed!

Matt