[WIP] Cog Railway Technic Style

[JGW3000]

Inspired by last summer's trip up the Cog to the summit of Mount Washington, New Hampshire (http://www.thecog.com/), I thought I'd give modeling a diesel cog engine a go. In order to get the correct spacing for the wheels, and placement of the cog sprocket, the first order of business was designing the cog track. I am focusing on the steepest "Jacob's Ladder" section, with a grade of about 37.4 % (20.5 degree angle from horizontal), which is nicely approximated by using a Technic angle connector #5 , which has an angle of 112.5 degrees (needed 110.5 for exact match)

Here is the final result, and yet another example of LDD's built-in background actually being quite authentic.

The actual diesel engine ascending Jacob's ladder

My first attempt was placing the support trestles parallel to the track (which was actually done in very old builds of the Cog, back in the 1870's time frame)

After looking at some images of the actual modern-day Cog, decided to be more authentic by placing trestles across the width of the track

This was not very satisfactory, as the trestle should get wider closer to the ground, and also needs cross-bracing parallel to the track,.after a few design iterations, this is the final version (verified by actual build with parts)

Another view of trestles and tracks together, about 1200 parts for six lengths of track, all BL'd!

Next step, to build the engine chassis, and then later do the bodywork. Here is what I have so far. Lots of work to do yet

Edited January 7, 2014 by JGW3000

[Eigenbroetler]

WOW, that is an interesting build!

I have never seen a cog railway before. well, i have probably seen one, but not thinking about how it works.

Edited January 6, 2014 by Eigenbroetler

[NevynPA]

YAY FOR TECHNIC TRAINS! Can't wait to see the build progress!

[jodawill]

Is the train going to be all Technic?

[JGW3000]

Thanks for the comments! The train chassis will be all Technic, with some Technic bricks used as well. Next step is to decide whether to use a train motor or an XL motor. I am tempted to use the train motor, but its form factor is a bit inconvenient for mounting the cog. In either case, will probably go with a chain drive to turn the cog's axle. The real engine has two cogs, each on the same axle as the train wheels, one on each of two 4-wheeled bogey plates (or something resembling bogies)

After I get the chassis worked out, with two cogs, I may decide on going for a steam-engine rather than diesel, so definitely will need to transition from beams to bricks at some point. May be easier as the steam engines used on the Cog appear not to have bogies, and there is a convenient tender for the battery box.

Edited January 7, 2014 by JGW3000

[Paperballpark]

Very interesting! I don't normally 'do' technic, and just happened across this topic while on the main forum page. However, I'm into trains, and having been on the Mount Washington Cog Railway about 15months ago, I have vague ambitions of recreating the steam train in Lego. I'd use system bricks though, rather than technic.

Nevertheless, I'll be very interested to see how this turns out!

[Rishab N]

Interesting. You don't see many technic trains. I can't wait to see how this will turn out

[Gee]

I'll be keeping tabs on this! I love railways but am a Technic fan, this blends the 2 and in a cliff railway! Awesome stuff, good luck with it!

[kieran]

Favorite 2 areas, looking forward to this

[TinkerBrick]

I would give the XL Motor a try. IMO it would hard the synchronize the Train Motor (for adhesive traction) with the (whatever PF Motor for) cog propulsion.

Anyway, great project. I like trains.

[Lakop]

I love the idea of train. I look forward to it.

H

[JGW3000]

Thanks for all of the support! Some considerations -

First, the track will be short, only 6 pairs, so maybe less than a meter in total length, primarily due to budget constraints. May consider expanding it in the future, but will have to be straight unless I figure out how to bend the tracks. With such a short length, not really enough room for both the engine and a coach, so I will focus on the engine first. Probably will be a combination of studless and studded Technic with some bricks, but I am getting a bit intimidated by the size, at 3-4x larger than a typical LEGO train engine. But since I don't need rotating bogies, this does help reduce the complexity.

I can use a train motor, as the engine will be 11 to 13 studs wide so plenty of room for all of the PF components plus gears. Using chain drives to connect the train motor axles to the actual train wheel axles and cog wheels may be a good approach. The train motor has great torque. I am also thinking of using 2 XL motors, one for each axle.

The real engines has the cog and train wheels on the same axle, as they have their own machine shop and so can make custom parts out of steel. We are limited in the choices of sprockets or gears that can be used that will work, so may end up having the cog and train wheels on separate axles. Waiting for some parts from BL to test out concepts I have been pondering.

As Technic goes, this will have just one function - hill climbing, but it will be a fun design for me. I will of course make updates as the work proceeds, but in the real world will be really busy at work until end of February, so may not have as much time as I'd like to work on this.

[TinkerBrick]

If the engine your building has the cog wheel on the same axle, it makes things easier. I was refering to European steam locos that even have a separate steam engine for the cog axle as it differs in sizes (usually much small and located on a lower level between the axles).

[LEGO Train 12 Volts]

Wow this project looks absolutely promising!

...and it should be moved to the train forum!

[JGW3000]

I got the cog/sprocket wheel and train wheels on the same axle last night, traveling now so will post some pictures tomorrow.

As this is a hybrid project, some cross-pollination could be useful, would prefer to stay in the Technical forum for now as the focus of the project is currently mechanical and not design.