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Here’s a model I’ve been working on this week of the Mount Washington Cog
Railway in New Hampshire.
For anyone unfamiliar with it, it’s a small steam-powered railroad that takes
passengers from the base of Mount Washington to the top. It was first built in
1869ish, and has morphed a bit over the years.
Due to the grade that the train must climb (about 36 degrees I think I read),
the locomotive uses a cog that meshes with a rack on the rail line to pull
itself slowly up the mountain. The full explanation is here:
Mount Washington Cog Railway
I tried to model the same behavior using technic gears and gear racks.
Cog
Rack
The other thing that I attempted was the distinctive tilted boiler. Because of
the steep grade, the boiler is tilted on the locomotive so that it is level when
the train is moving up and down the mountain.
Locomotive
Power for the model is supplied by a standard battery box hidden within the
passenger coach. This required that, unlike the real train, I tether the coach
to the locomotive. This turned out to be a good thing though, as the locomotive
was back-heavy, and tended to flip over without the weight of the coach holding
the front end down. I built switches for the battery box into the roof of the
coach so that I don’t need to open it up every time I want to change direction.
I made an AVI file of the train moving up my test track, which I’m estimating to
be about 30 to 35 degrees.
Climbing
the Track
I’ve run it at up to 45 degrees, but it occasionally slips as the locomotive
wants to tip backwards, which disengages the gears from the rack.
Now I just need to get enough bricks to build Mount Washington.....
-Elroy
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In lugnet.trains, Elroy Davis wrote:
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Here’s a model I’ve been working on this week of the Mount Washington Cog
Railway in New Hampshire.
For anyone unfamiliar with it, it’s a small steam-powered railroad that takes
passengers from the base of Mount Washington to the top. It was first built
in 1869ish, and has morphed a bit over the years.
Due to the grade that the train must climb (about 36 degrees I think I read),
the locomotive uses a cog that meshes with a rack on the rail line to pull
itself slowly up the mountain. The full explanation is here:
Mount Washington Cog Railway
I tried to model the same behavior using technic gears and gear racks.
Cog
Rack
The other thing that I attempted was the distinctive tilted boiler. Because
of the steep grade, the boiler is tilted on the locomotive so that it is
level when the train is moving up and down the mountain.
Locomotive
Power for the model is supplied by a standard battery box hidden within the
passenger coach. This required that, unlike the real train, I tether the
coach to the locomotive. This turned out to be a good thing though, as the
locomotive was back-heavy, and tended to flip over without the weight of the
coach holding the front end down. I built switches for the battery box into
the roof of the coach so that I don’t need to open it up every time I want to
change direction.
I made an AVI file of the train moving up my test track, which I’m estimating
to be about 30 to 35 degrees.
Climbing the Track
I’ve run it at up to 45 degrees, but it occasionally slips as the locomotive
wants to tip backwards, which disengages the gears from the rack.
Now I just need to get enough bricks to build Mount Washington.....
-Elroy
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Interesting model. Strangely I keep finding that I’m thinking microscale each
time I see the pic!
I was wondering why you alternated the rack from side to side of the track? Did
you find that this gave a more reliable grip? Also, have you experimented with
curves? I’m thinking that your alternating method would make curves more of a
realistic proposition as the four long rack elements do actually connect between
the sleepers (ties) on curve with care (or brute force!) This
model has the rack set (it looks like) 1 1/2 studs of centre which obviously
works but is not as realistic.
I see that your model is pure rack propulsion, is the Mount Washington Cog
Railways pure rack or rack and adhesion?
Tim
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In lugnet.trains, Tim David wrote:
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I was wondering why you alternated the rack from side to side of the track?
Did you find that this gave a more reliable grip? Also, have you experimented
with curves? I’m thinking that your alternating method would make curves more
of a realistic proposition as the four long rack elements do actually connect
between the sleepers (ties) on curve with care (or brute force!) This
model has the rack set (it looks like) 1 1/2 studs of centre which obviously
works but is not as realistic.
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My original actually had two gear racks running up the center of the track. I
didn’t have very many though, so I ended up taking out every other one so that I
could make a longer run.
I actually did test it with curves. Alternating the pieces does allow the rack
to make it around curves. I didn’t test it at much of an angle, but with what I
did test, the train ran almost as smooth as it does on straight track.
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I see that your model is pure rack propulsion, is the Mount Washington Cog
Railways pure rack or rack and adhesion?
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The real thing uses a pure cog solution. The steam engines drives the cog,
which pulls the locomotive up the mountain. What I thought was interesting is
that the locomotive and the passenger coach aren’t actually coupled together.
The reason for this is for safety. The coach is braked seperately, and uses
some sort of ratchet type system to hold itself in place. This way, if the
locomotive fails for some reason, and starts to roll back, the passenger coach
will stay put instead of rolling down the mountain too.
-Elroy
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