Subject:
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Re: New MOC: 4-8-4 Northern
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Newsgroups:
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lugnet.trains
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Date:
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Fri, 9 Jan 2004 07:38:07 GMT
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Viewed:
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1817 times
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In lugnet.trains, Shaun Sullivan wrote:
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Hi All,
Well, after at least 8 months of on-again off-again effort, I’ve finally
finished up my 4-8-4 Northern Steam Engine:
The most amazing thing to me was the sheer size of the engine; I stayed true
to a minifig-compatible scale of a little bit more than 1 foot per stud, and
the resulting locomotive is a monstrosity! You can see a side-by-side
comparison of it and my Hudson engine (which had been my largest engine):
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Excellent model - you’re a man after my own heart! Great to see someone else
building to 8mm:1ft scale or thereabouts!
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Features include:
(1) Working pistons; as with the Hudson, there are two per side - the drive
piston and the valve piston. The pistons here actually have the least
friction of any of my designs to date - on straightaways they work
brilliantly! On the curves, the drive wheels do not ride on the rails of the
track, so the pistons do not move.
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Could you try adding Walschaert’s valve gear, as I did with my British Class 9F
2-10-0 and LMS Garratt 2-6-0+0-6-2? You can use the ++ pieces for the valve
gear cranks and a dark grey 3+stud pin for the main rod crank with model team
wheels.
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(2) Lower-angle variation on the robot-arm cowcatcher design.
(3) A working front light
(4) For the first time, I have a steam engine that is *pulled* by a motor in
addition to being pushed by the tender! This was practical due to the
enormous size of the engine - for once, the standard LEGO train motor was the
right scale to be in the leading truck.
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That’s good - big engines need more motors, especially with prototypical length
american trains! I have plans for a Northern myself, just haven’t got
sufficient pictures or drawings yet. This was going to have one motor under the
firebox and two under the tender. I use a beefy 3 Amp smooth power supply too,
as the Lego controllers can’t move such monsters!
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(5) The second large “smokestack” coming off the main steam cylinder is
easily removable. Beneath it there is one of those large aqua-colored
Fabuland buckets. I don’t know if it will work, but sometime I’d like to
drop some pieces of Dry Ice in the bucket and see if any “Steam” escapes
through the stack. My main concern is that the cold temperatures might
induce cracking in the bucket ...
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Interesting! Modellers of OO and HO at railway exhibitions have asked me if I
could do Live Steam - this seems to be the only way of doing it in Lego.
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(6) One of my favorite features is the use of 1x2 panels and 1x1 corner
panels, mounted horizontally, to produce the “ledge” that runs the length of
the cylinder. I first experimented with this on the 0-4-0 Yard Goat, but I’m
particularly happy with how it came out here.
The main downside to the design, as it stands right now, is that it cannot
really handle corners. However, the challenge isn’t at all what I expected;
when going around a curve, the engine leans out a bit, since it is no longer
supported by the drive wheels (Which have slid inside the outer rail of the
track). Once the engine starts coming out of the curve, the outside drive
wheels are below the level of the rails due to the tilt, and rub against the
inside of the rails instead of riding up on top of them. Evantually, as the
engine continues to come out of the curve, the rubber drive wheels bind
against the rail altogether, bringing the engine to a stop. I haven’t relaly
spent much time thinking about this yet, so any ideas are welcome!
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Such an engine would never go round a 40ft radius curve in real life, so don’t
put two Lego curves together in the same direction on your layout. I space all
of mine out with 1 straight in the yard (=80ft) and 2 on the main line (=120ft),
so that scale trains can go at a reasonable speed. What’s the maximum speed of
the prototype for this engine in real life?
I’ve not had tilt problems with my engines, but I usually suspend the wheels off
the rails altogether and use two technic 71427 motors to power them - gear ratio
8-24c-8-24c-8 at motor level, with 20-12 from the middle 8 tooth cog down to the
driving axle with the valve gear on it. The engine has a 4-wide frame of
technic beams, giving holes for gear axles and a strong inner structure.
This has given me much food for thought - I’ll look for the encyclopedia someone
suggested.
Mark Bellis
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Message has 1 Reply:
 | | Re: New MOC: 4-8-4 Northern
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| (...) Hi Mark, Thanks for the feedback! I finally tracked down some photos of your trains. With respect to the Walchaert's gear, are you referring to the following? (URL) having a tough time pictureing your description ... do you have a link to a (...) (21 years ago, 9-Jan-04, to lugnet.trains, FTX)
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Message is in Reply To:
| | New MOC: 4-8-4 Northern
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| Hi All, Well, after at least 8 months of on-again off-again effort, I've finally finished up my 4-8-4 Northern Steam Engine: (URL) The most amazing thing to me was the sheer size of the engine; I stayed true to a minifig-compatible scale of a little (...) (21 years ago, 3-Jan-04, to lugnet.trains, lugnet.announce.moc, lugnet.org.us.nelug, FTX) !!
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