LDD MOC: Porter 0-4-0

[greenmtvince]

Ever since the indiana jones track was released, I've been inspired to build my own narrow gauge railroad. I was a huge fan of Carl Arendt's Micro/Small Layout Scrapbook and looked forward to his twice a month updates for inspiring small layout designs. He inspired my 2' by 4' rendition of the Claremont Concord Railroad while I was in Afghanistan. My dream was to build a pizza layout with the narrow gauge track and have it featured in one of the Pizza Layout Specials among traditional modeller's railroads. Unfortunately Carl passed away earlier this month and my dreams of him featuring my layout are no more. However, I'm still moving ahead with my plans in his memory.

I settled on the smallest and one of the most widely produced locomotives for narrow gauge industrial railroads, H.K. Porter's 0-4-0. With a saddle tank of course to help me hide some of the troubly bits.

The trick of this was figuring out how to fit a power source and motor into such a small chassis. It turns out that a Micromotor on full with a 5:3 gear ratio from the bezel gears moves at a pretty respectable speed with some decent torque. The 9V power supply was a bit of a challenge, but the mechanics of which I'd already worked out withmy Alco S4 for my layout in Afghanistan.

Big Ben's Medium drivers seemed a bit too big for this project. So I threw a set of lego train wheels onto a bridgeport end mill, did a few calculations, and had my own custom small drivers. While some purists might consider this cheating, I don't consider it any different than using BBB's custom wheels.

After that, it was just a matter of making it all look right. Several hours with Lego Digital Designer and here's my work:

Let me know what you think and how I could improve. I'll be turning to brickshelf tomorrow to order the remainder of my needed parts.

[SavaTheAggie]

I'm sorry to hear about Carl's death, but this project will be a great way to honor him. The locomotive looks pretty good so far. The only real nit pick I can provide is that the boiler looks too long - comparing the two profiles, the drawing and your LDD image, it looks like the cab needs to be moved forward one stud.

As for the wheels, I would have gone with Ben's small train wheels and just used a technic crankshaft to turn them into drivers.

http://www.bricklink.com/catalogItem.asp?P=2853

I've seen this done before and it works well, I plan on using it on an upcoming diesel that uses siderods like a steam engine.

I would be concerned about your micromotor. While it does fit within the confines of your engine, they're not designed for much load. Given their rarity and expense it would be a real shame to burn one out. I would suggest considering a piece of powered rolling stock, where you'd have more room to stuff a cheaper and stronger motor.

--Tony

[Fuzzylegobricks]

I think it is good. I am sorry your friend passed. The wheels though are hard to tell that there even there, so maybe you could have a little bigger wheels.

[roamingstop]

I think it is good. I am sorry your friend passed. The wheels though are hard to tell that there even there, so maybe you could have a little bigger wheels.

Space2310 did some real nice Technic powered bogeys for the I-Jones track, and perhaps his technique can help. It was posted in eurobricks and also I think on railbricks site. But fitting them into a model (e.g. in the boiler) might be a bit difficult.

Edited March 30, 2011 by roamingstudio

[greenmtvince]

I'm sorry to hear about Carl's death, but this project will be a great way to honor him. The locomotive looks pretty good so far. The only real nit pick I can provide is that the boiler looks too long - comparing the two profiles, the drawing and your LDD image, it looks like the cab needs to be moved forward one stud.

Thanks for being nitpicky. I followed your suggestion and it looks much better! Thanks for being nitpicky where I wasn't.

As for the wheels, I would have gone with Ben's small train wheels and just used a technic crankshaft to turn them into drivers.

http://www.bricklink.com/catalogItem.asp?P=2853

I've seen this done before and it works well, I plan on using it on an upcoming diesel that uses siderods like a steam engine.

Hmmm, I'll have to see how you use this. I don't think it would work for my application if the locomotive drive wheels are motorized. Maybe by changing my transmission, possibly to something using a worm gear it would work. The crankshaft might push the drive rods and pistons out a little far out for such a small model, whereas I have them mounted flush right now.

I would be concerned about your micromotor. While it does fit within the confines of your engine, they're not designed for much load. Given their rarity and expense it would be a real shame to burn one out. I would suggest considering a piece of powered rolling stock, where you'd have more room to stuff a cheaper and stronger motor.

--Tony

Thanks for bringing that up. It does make me concerned for the motor. I'd really like to avoid using powered rolling stock if at all possible since I didn't plan on building anything that could hide another motor any better. Is there a way to not burn out the motor but still use it in this application?

My understanding of motor burnout was that it occurs when insulation melts from either high currents at stalled torque, normal wear and tear, and motors that produce a lot of heat by design. Looking at Philo's page. It seems like the micromotor produces a good amount of torque, a little less at the wheels with my transmission but for a higher RPM. My assumption is that I can keep wear on the motor down by not running it constantly at shows and keeping it away from stall torque. I'd love to hear from anyone with some expertise on the motor.

Failing that, is there a close commercial substitute that I could crack the case open and replace the actual motor should it burn out?

I think it is good. I am sorry your friend passed. The wheels though are hard to tell that there even there, so maybe you could have a little bigger wheels.

Thanks for your thoughts, I wish I'd known Carl other than through his articles. The wheels on the Porter are small anyway though. I think I need smaller siderods!

Space2310 did some real nice Technic powered bogeys for the I-Jones track, and perhaps his technique can help. It was posted in eurobricks and also I think on railbricks site. But fitting them into a model (e.g. in the boiler) might be a bit difficult.

Space's work was really inspirational to me, especially his narrow gauge switch track. I'll post a picture tomorrow of the chassis and drive mechanism I've worked out for this train. It's less complex and far less elegant than his design.

Edited March 30, 2011 by greenmtvince

[greenmtvince]

Alright, based on Tony's nitpicking. Here's my revision:

And here's a couple detail shots of the chassis and transmission.

[SavaTheAggie]

Much better, it looks much more like the prototype now. I'm actually tempted to build non motorized version just to have it, though I don't have any narrow gauge track (I'd like to change that). I can just see one of these little narrow gauge engines pulling out of a mountain canyon to a large yard and to one of my bigger standard gauge steamers.

To your motor issue - I'm now even more concerned. You've got the gearing set up so that the motor is turning at slower RPM than the wheels, which is going to cause even more stress. I would at least use 1:1 gearing ratio, if not gearing it down even more than that to save the motor.

You asked about an alternative - unless you're willing to make a full boxed-in freight car to hide a larger motor, I don't think anything but a third party motor will work for you.

If it were me, I would probably create two box cars (or similar solid wall car) along with all the other rolling stock my train would be pulling. In one, the first box car behind the locomotive, I'd put a geared down PF Medium motor. In the second I'd put the $50 rechargeable PF battery, with of course a wire leading from one to the other. I would choose the rechargeable battery because it has a speed control on board, so there wouldn't be much need to use an IR receiver (which would only take up more room).

That may not fit in your vision, but it would certainly be a workable solution.

--Tony

Edited March 31, 2011 by SavaTheAggie