Not much discussion of the boiler (some at around 7:20) but I can't figure out how the firebox is stayed.

Really good video detailing the recent construction of another X class 0-8-0RT rack and adhesion steam locomotive for India’s Nilgiri Mountain Railway. The locomotive is largely a copy of the locomotives built by the Swiss Locomotive Works (SLM) in the 1950’s. Apparent improvements over the originals include welded boilers and stainless steel water tanks.

https://youtu.be/g9P1RMseLh0

Hugh -

Very interesting video. Not to nitpick, but isn't this really an 0-8-2 tank rather than an 0-8-0?

Les

- Track Rack - not familiar with rack railway practice, the track rack has two spur racks offset by 1/2 pitch. Curious if this provides similar benefits if progressive tooth engagement similar to helical gears but without the side thrust?

- Rack Pinion Drive - it looks like the rack pinion drive is independent if the adhesion drive but wonder if they have a clutch that they can be interlinked? Perhaps once they engage the rack, base load the rack pinions and assist with adhesion? … or control separately.

The newly rebuilt cog line on Pike's Peak now has a double rack system. I believe this is a Swiss system, and likely has the advantage you state.

They can't be mechanically interlocked, as the cog wheels are different diameter than the drive wheels, therefore each set of pistons runs a different speed. If they were on a common throttle, that could lead to a situation where the drive wheels just slip uncontrollably. So, there are either two throttles or a transfer valve that selects which cylinders receive steam, but the cab shots aren't clear enough to tell.

Now, I want to point out one of the most bizarre features of the previous oil burning new-builds. They use some kind of electric spinning cup (home furnace) burner, and thus need electricity. So they are fitted with electric generators where the coal space would be. You can see it in this video. I think the decision to build the next engine as a coal burner was a realization that this was a really bad design choice.

https://www.youtube.com/watch?v=PvLUadY5rZY

Really neat. The work seems to be high quality too. One thing for certain: labor in India is far cheaper than here. The lack of PPE, especially eye protection, is alarming.