Crayons schrieb:

> Ah, interesting. Not being a train enthsiast as such I often wonder why trains
> such as these contain so much complexity in comparison to others. While at the
> same time not being sure if I would understand the answer if someone gave me a
> lecture on it! The quantity of linkages involved seems rather overboard.

There's probably one simple reason why your train doesn't exhibit that 
many rods and things: The valve gear (the subset of the rods controlling 
the steam valve timing) is probably hidden well behind the wheels.

Later trains also added more complexity to the valve gear for 
improvements; the valve gear of all but the earliest locomotives allowed 
for variation in the valve timing - primarily to switch between forward 
and backward motion, but also to "throttle" the engine's power to save 
fuel when the train was well in motion. In earlier designs, the 
necessary mechanism took quite some space, and included motions that 
resulted in a lot of wear and tear, and/or required much human power to 
change the valve setting. Later designs took care of all these problems, 
  but of course were somewhat more complex.

As for the other "greebles" on a train, those typically feature...:

- Valves to drain condensed water from the cylinders (typically two 
below each cylinder)

- Pipes to feed fresh water into the boiler (later engines were legally 
required to have two independent water feeding systems, as a lack of 
enough water in the boiler would almost inevitably lead to a boiler 
explosion, due to melting of the firebox; often, feedwater was inserted 
at the front of the boiler, away from the firebox; fun fact: The 
standard device used for this purpose used the pressure in the boiler to 
feed water /into/ it... black magic to me, but it must have worked!)

- Sandboxes and associated pipes (most trains carried the sandboxes on 
top of the boiler, with pipework leading to the wheels, plus some 
pipework for steam, as many used steam pressure to assist in sanding)

- Pipework (and valves of course) to blow steam directly into the 
smokestack, bypassing the cylinders, to draw air through the firebox 
while standing still or moving slowly

- Mechanical brakes and associated gearwork (usually hidden between the 
wheels)

- Systems for automatic lubrication of the cylinders (seen in later engines)

- Systems to generate dry pressurized air for the automatic brakes that 
became mandatory in later times (typically a steam-driven compressor, a 
few cylindrical pressurized air tanks usually situated beneath the 
catwalk along the boiler, and /lots/ of pipework leading back and forth, 
with the sole purpose of cooling the air)

- Systems to generate electricity for the electric lights on later trains

- Systems to automatically feed coal into the firebox (on very heavy 
engines; the USRA Santa Fe features such a system)

- Systems to automatically pick up water from trenches between or beside 
the track (on some engines) to reduce the number of required stops.

- Maybe one or two other systems I forgot to mention (or don't even know 
about)


> The train I modelled is a modified Hall Class from the Great Western Railway and
> I only had one basic overall blueprint of the dimensions to work from
> http://www.greatwestern.org.uk/loco_draw.htm

That's not as much as I had, but at least it features dimensions. I've 
seen far worse that still called themselves "blueprints".

> Indeed! I downloaded as many as I could find but sadly everyone seems to take
> that same picture, from in front a few yards up the station platform! What was
> really helpful was actually contacting a train forum and asking there for what I
> called more "pornographic" pictures of details under the platform as it were! I
> got some very good images sent to me that way. One particular area that I was
> struggling with was underneath the footplate steps to the cabin area. I knew
> there was a sandbox there but only blurry images of that whole area. I managed
> to concoct the attached image from images from one very helpful chap in
> particular.

Looks like you got hold of some real "hardcore porn" ;-)

So far I have limited myself to "softporn" readily available on the net.

> I guess I concur with the earlier posting asking whether the bevelled edges code
> element is likely to become available???

It is pretty likely to; give it some time though.

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