jtlan

Thanks. That's so undiscoverable...

Here's some footage I took of the locomotive moving some gondolas and pulling two Umbauwagen, to give you a sense of what it can do. Does anyone know how to embed video with the new posting tools?

If you aren't pulling very heavy loads, you can use this technique to apply "painted-on" traction tires. I used that technique on my Glaskasten, and it ran multiple days at a show pulling a pair of two-axle cars. Also, beware the crank holes! They are sqrt(2)/2 studs away from the axle, rather than a whole or fractional number.

You won't be able to use the older pack with the receiver without some hacking, as the converter cable is not wired to connect power sources to the 9V/0V lines. A 9V cell has a lower capacity than a pack of AAA cells (if only because, for the same battery chemistry, capacity is proportional to battery volume). If you run the train a lot you should expect to change 9V cells frequently. You can probably get a few hours of continuous running, depending on the load. That said, you could also connect the 9V battery box directly to the motor -- no receiver. You won't be able to do any yard work, but you can recreate that 4.5V train experience. Kind of refreshing actually!

Unfortunately, due to a half-stud offset there's only room for one belt. I would get a bit more torque if I could find a thinner pulley for the worm shaft (the belt would be wedged in to the groove, increasing friction), but I'm reasonably happy with how the locomotive drives now. I haven't tried pulling anything too heavy, but at the BayLUG Holiday Show it was able to rescue my Standard Class 2 and a short string of 2-axle cars. Good point on the switches -- I've only tested with 9V, and I know that the geometry of the guides is slightly different on PF tracks. The locomotive isn't that light, so it's not so much that it derails as it ... ignores the switch and goes straight instead.

Thanks, ColletArrow! I tried using the sliding gear, but the extra half-beams required to center the gear added extra friction, so I went with this design. The axle doesn't slide very far (5.5 axle in a 6-wide space), so the gear doesn't actually disengage from the worm. Thank you, Legoman. I think the issue with the center windows is that they're slightly too far up (due to the thick sill at the bottom of the window piece). The locomotive goes through switches just fine, except when coming out of a curve into a switch that's also set to turn the same way: ... and even then, it only happens with one orientation of the locomotive. I've had success with the same wheel arrangement in unpowered rolling stock, so it must be something about the dynamics of the transmission. Thanks McWaffel! I enjoy the challenge of building compact mechanisms into small locomotives. The weather's been poor here so I haven't had a chance to take footage (the photos were taken in a small dry spot on the porch). Thank you, Zephyr. The "1 plate thick corner pillar" is an ever-present challenge when modeling diesels. I'm pretty happy with the wrap-around solution I came up with using the small panels.

Want an SD40, but can't afford one? Here's a half-off deal for you: ...literally. These little locomotives are made by cutting an SD40 in half, attaching the frame to the truck, and installing a new and efficient prime mover and cab. I kid you not: Link to the manufacturer's website. I went about building this model the same way I usually do: Gather reference images, find an engineering drawing, and overlay grid paper over the scaling drawing. Complicating the matter was that the diagram in Tractive Power's specifications brochure was very obviously wrong -- there's no way the SD40 truck is that long! Comparing the drawing to photos of the real locomotive confirmed my suspicions. I overlaid a drawing of an SD40 truck on the diagram of the body, and worked from that. As with my Standard Class 2, I selectively compressed the wheelbase to make the axle-to-axle distance a whole number. This made building the truck frames much easier: After working out the frames, I worked on designing a drive train that would power all three wheels (once again, I picked a small prototype, which didn't help). Here's what I came up with: That's the ungeared 9V motor driving a shaft with a belt, powering all three axles with worms. The center axle slides to traverse curves: As a side bonus, I get to check another motor off my list of "motors to power a locomotive with". Because of the belt drive, unlike any of my other locomotives this locomotive's pulling power is limited by torque instead of weight (because the belt will slip first). It still has plenty of pulling power for something of its size. The locomotive traverses almost all track arrangements -- strangely, it will skip switches coming out of a curve, but only in one direction. The hood hides the battery box. One section isn't held on by anything, and comes off to reveal the power button: The other sections are only connected with one stud (and some interesting panel spacing to grab the power connector), making it easy to change the batteries. The receiver sits on top of the motor in the cab and receives signals through a hole in the roof. Unlike the other locomotives I've built, this one has great reception from all angles. I really wanted to build this locomotive in Curry Rail colors, but the parts I needed weren't available in either teal (too old) or bright green (too new?). So I built it in black, but left the frames grey to show the details better. Thanks for reading! Full Brickshelf gallery, pending moderation.

Welcome, sinclair1. Lego sells an official adapter that goes with the battery box, but there's no need to pay so much for that. Any DC adapter whose plug fits in the battery box and produces between 8V and 18V should work. You probably have a suitable one in your house already from some old electronics (modems, etc). Here's the chart from Railbricks 7:

Thanks, Zephyr (although there is actually a pair of curved slopes on the pistons!). The prototype's roof, bunker, and side tanks are angular, so slope bricks are actually the best representation for those parts: The boiler is slightly oversize to properly cover the PF components. Maybe it's because I grew up building that way, but I think the 45-degree slope bricks are one of the best ways for rendering a 4-wide boiler.

Greetings Train Tech, This MoC was actually built over a year ago! I originally designed and built it for use as a "demonstrator" model for a how-to post on Power Functions steam locomotives that I haven't gotten around to writing (although the precursor post is available). While we're waiting on that, I figured I might as well post this model. Prototype History British Railways built this class of 2-6-2 tank engines for a mixed traffic role. Apparently they were very similar to the LMS Ivatt Class 2 2-6-2T, from which they were derived. While none of the class survived into preservation, The Bluebell Railway is rebuilding one of the related 2-6-0 tender locomotives into an example of this class. Engineering Details Usually when I build a MoC, I start with the prototype in mind, then work towards the model. This model began with the desire to build "a small steam locomotive to demonstrate Power Functions", which then determined the choice of prototype. The Standard/Ivatt Class 2 has a number of helpful features in this regard: Small tank engine Large bunker could hide a Power Functions receiver Side tanks can cover up other Power Functions components And indeed, that's how the locomotive is laid out: Even so, the locomotive is quite cramped -- there wasn't enough room for an M-motor based transmission, so I went back to the trusty 9V gearmotor. The output shaft of the motor is very close to the driving axle: ... and it took me a couple tries before I found a good solution: The side tanks contain a channel that allows a cable to pass through, connecting the motor and receiver: The power button is on top of the smokebox and is only held in by gravity: Thank you for reading. Full Brickshelf gallery here.

The voltage of fresh alkaline batteries drops off pretty quickly, so they won't actually deliver the full 1.5V for most of their usable life. I would compare against freshly charged Eneloops (be sure you're using a good charger, like the one that Panasonic supplies with them), and see how they behave. Any chance we can see pictures of what you're working on?

I believe Lego has designed the large wheel to take this rubber band (in red -- in my experience the other colors represent slightly different sizes). On my locomotives I use these O-rings (to better match the black wheels) and haven't had any traction problems.

There are two factors that determine the pulling power of a locomotive: Torque is how strongly the motor turns. Torque can be increased by using a more powerful motor, gearing down the motor, or using a power source that delivers more current. Traction is how tightly the wheels grip the rail; the locomotive's wheels must be able to push against the rail and not slip. Traction can be increased by using traction tires with a higher coefficient of friction, or increasing the weight of the locomotive carried by the driving wheels. In my experience, I've found that traction is almost always the limiting factor for Lego models. People running into pulling power problems with their models are usually encountering the limits of traction rather than torque. With that in mind: Unless your batteries are very dead, I find it very likely that the L-motor would stall unless an axle is actually jammed -- it's very strong. What kind of batteries are you using? Do the wheels on your model slip when it runs? With something like a 4-4-2, I would imagine it's difficult to get a design that puts enough weight on the drivers. If you could include pictures of your model, that would help us figure out what's going wrong. Without seeing your particular wheel and motor setup I can only make vague guesses as to what kinds of problems you're encountering.

Welcome to trains! The train wheels and wheel holders are available from online Pick-a-Brick, but strangely the axles are not. A lot of builders wind up using Big Ben's wheels anyway. The Emerald Night is mostly expensive because of the passenger car included in the set. The parts for the locomotive won't set you back that much (particularly if you build it without the printed curve slopes -- or in a different color!). The parts in the My Own Train sets are pretty common and you should find it easy to acquire them. My post on my building process covers the scaling process I use. On my mac, I use a program called Pixelmator to make the scaling drawings, but any basic image editor should have the necessary features (layers, scaling, and recoloring). Other people have had success with Sariel's scaling tool, but I personally prefer seeing the entire grid. The trickier part is usually finding the scaling drawings and doing the math! Some of my locomotives contain a lot of Technic, so the line is kind of blurred for me... Once again, welcome to trains! Come by any time you've got questions, this community is quite helpful.

Building a proportional model without a scaling drawing is like working blind. However, overall you seem to have done pretty well. I made a scaling drawing to figure out where the discrepancy is: Click here for full size. The gist of it appears to be that, at the scale you're building at the Vectron's wheels are closer in size to Big Ben Bricks' medium drivers than they are in size to the flanged wheels. In fact, we could have discovered that by scaling down Seimens' quoted size for the wheels by the scale you appear to be using... In LDD, try substituting this arrangement for a medium driver: (Note: the hole in the medium driver is not the same distance from the axle as the holes in the pulley). Let me know how it goes.

I've had some success with these. As for weights, adding a AA battery box or something like that should be sufficient.

See my narrow-guage train for a self-contained implementation. It's somewhat tall, however.

For what it's worth, I've never had an issue powering connected drivers through the connecting rods (sample size: 3 steam locomotives). Neither has @Commander Wolf. In most cases the weight of a locomotive is an impediment to pulling power long before the strength of the drivetrain is. I'm not sure why your driving rods are popping off, as I've never used the printed ones. The pulling power of those locomotives was enough to pull two Umbauwagen at a decent pace, and I wouldn't expect your Pullmans to be a lot heavier (573g each). But perhaps they don't roll as smoothly? For that matter, the wheelbase on the tender looks really long. Do you only have pulling problems in curves? Aside regarding gears: Generally geared transmissions are very efficient. However, most Lego designs for the frames supporting those transmissions introduce a lot of friction. There is an art to designing a rigid frame that does not overconstrain the axles passing through it.

How much stuff are you trying to pull, and how fast? 2x L motors is fantastically strong, but I'd be wary about speed and controllability. Is it geared 1:1 to the drivers? I can't see exactly how your leading and trailing wheels are attached, but it seems like the height might be off on either the front or rear wheels, which will lift the drivers. Can you post closeups of the connections?

Thanks, Barduck. From instruction buyer to maker! A number of people here now have said they sell instructions to offset the cost of the hobby. I'm surprised that there's enough volume for that -- maybe they're more popular than I thought?

SecurityMan and other companies make small wireless cameras that are powered from 9V batteries. I remember seeing a hobby shop demonstrate them in their trains section many years ago. With the low cost of drones now it might be cheaper to cannibalize a camera from one of those! In prior years I took footage of the BayLUG layout using a small flatcar with my phone on it: However, it holds the phone such that the camera faces in/out of the layout. This year @codefox421 used some GoPro cameras to shoot footage.

This car looks pretty long (and the underbody seems pretty close to the trucks). I suggest building some mockups (using whatever random parts you have available) to make sure they work around the Lego curves and switches.

Thanks, Holger. What changed your mind about people rebuilding and selling your models? And how did you come to be asked to write a book? Thanks, Tony. Instructions as teaching (literal "instruction"s?) is a pleasant surprise, and I'm impressed that you can convey that in a booklet. What would you say is your best work on that front? Since you model mostly American locomotives, do you find that most of your customers are in the US?

Hello Train Tech, I have seen some people selling instructions/plans for train MOCs. Out of curiosity, I have some questions for those of you who have bought or sold such things: BUYERS Why do you buy MOC instructions? Which instructions did you buy? Why did you choose those instructions? Do you prefer printed or digital instructions? Why? Could you share some particularly enjoyable or frustrating moments from using the instructions? SELLERS Why did you start selling instructions? How do you choose which models to offer instructions for? Are there models you started working on with the intent of offering instructions for them, rather than as an afterthought? Could you share some particularly enjoyable or frustrating moments from making and selling instructions? Many thanks to anyone who answers -- I'm genuinely curious to know!

That's an adorably tiny locomotive. I like the use of the yellow Duplo piece on the last car, which reminds me a bit of the coverings on coil cars. The entire setup looks very much like some narrow-gauge industrial railroads. It seems like the bridge would be a bit more rotted in a swamp, no?