aj_bricks

Thanks, @Brickwolf! @Rubenhof, sent you a Flickr message. I don't have a complete list like that, but happy to help you build your own similar loco if I can.

Thanks, @Rubenhof! I don't have a complete file to share, but I'm happy to offer advice if you're building your own. I'll respond to your Flickr message and we can chat.

Those look neat, I hadn't seen them before. Thanks! I don't have room for those in this design right now (thanks, @supertruper1988 for the measurements) but I'll keep it in mind for the future. I re-worked the gearing on the drivetrain to 20:12 instead of 1:1, and man did it make a difference! I'm very happy with the speed now, and even without making changes to the middle axles (yet) there doesn't seem to be any trouble on R40 curves. I also used the rechargeable 9V batteries I mentioned earlier (https://www.amazon.com/dp/B07BT4D99D/ref=cm_sw_r_cp_apa_i_UkwoEbBA9HA5M), and I was impressed with them. The below videos show the locomotive running with and without a load of a couple container cars. I let it run at full speed pulling the cars and it was just over an hour before the battery dropped to 7V (even then there was not a noticeable drop in performance). https://www.flickr.com/photos/185494316@N03/49547931527/in/dateposted-public/ https://www.flickr.com/photos/185494316@N03/49547702601/in/dateposted-public/

Yes, a 9v battery will deliver enough power for 2L motors. But as @supertruper1988 and @izx pointed out, it won't last as long as what you would be used to with a standard Lego battery box. That being said, I ran it for about 15 minutes or so during the above test with no noticeable drop in performance. I used a duracell 9v that runs about 300mah. And more powerful 9v batteries are out there, like this set of 800mah rechargeables: 9v Lithium Batteries, Li-ion Rechargeable 800mAh 3 Packs with Quick Charger https://www.amazon.com/dp/B07BT4D99D/ref=cm_sw_r_cp_apa_i_UkwoEbBA9HA5M. I plan to use those if I ever take this to a show, though I might try the battery box izx mentioned if the dimensions check out. I'll run a longer test next time to see how much more the duracell has left (I'm guessing not much). As for the trucks, thanks @zephyr1934 and @jrathfon for the suggestions. I wondered about removing the rubber o-ring on the non-powered middle axles or even just replacing them with standard Lego metal axles, thinking the extra room in the technic hole might allow the axle to float up high enough to limit resistance. Once I get the parts for the change in gearing I'll test these other changes too.

Haha, thank you! That means a lot, especially coming from someone like yourself! Thanks to all for the comments, I apologize for the delay in adding more details here. I've been busy and had time to do more work and testing on the loco until recently. As this is my first time working with power functions motors, batteries, and the like, I seriously underestimated the difficulty in fitting everything inside the 5-wide main body. Wires can take up a lot of space! I budgeted space for 1 9V battery, 1 SBrick, and 2 PF L motors. I had seen the 9V battery-to-PF adapters offered by BrickTrainDepot, and figured I could make my own. I hadn't soldered in 4+ years, so it wasn't pretty, but it's functional so it works for me. I already had an arduino 9V power supply with a 2.1mm plug, so I acquired another 2.1mm socket and attached the PF plug to that. This gives me an extra way to disconnect the SBrick without having to fiddle with the battery connection itself. Once all the wiring was in the loco I realized I would have to compromise something to make room - so I knocked out the back wall of the cab and used that space for the PF connections. (Note: I think it's great that you can power the SBrick from any of the connections, top or bottom, because in my case using the bottom plug would make it too big to fit. For this reason I also had to connect both motors to the same SBrick port using a jumper cable.) I then ran it on my small temporary test track, since I don't have a permanent layout right now. The results were mixed - I was relieved to finally have it running as expected with all the electronics inside and pulling cars, but the 1:1 gear ratio makes for a slow drive (no surprise there) and the trucks seemed to get bogged down on the R40 curves more than I expected. Before building I had tested the truck configuration using 6 regular trainsets at the same spacing, but that didn't seem to have the same issue. I plan to do further tinkering for both - some small changes to the middle axle of each truck and the addition of 20-tooth gears to change the gear ratio. Below is the video of the test. https://flic.kr/p/2inWSxg

This is my newest locomotive, and my first attempt at building in 1:48 scale. KiwiRail DXC locomotive from New Zealand. Measuring 44 studs long and 7 studs wide, it can handle standard Lego R40 curves and is powered by 2 PF L motors (one on each truck) controlled by an SBrick. The custom stickers were made by OKBrickworks and I think they turned out perfectly! DXC class locomotives originally started as General Electric U26Cs, built in the 1970s. Similar engines were also produced for Brazil, Kenya, South Africa, Tanzania, and Zambia. DXC locomotives are used by KiwiRail on the South Island of New Zealand to haul heavy freight and the famous TranzAlpine excursion train (considered by many to be among the world's most scenic train rides). They differ from other DX variants in the addition of "chutes", special air intakes that are needed for better air flow in the 5+ mile-long Otira tunnel under the Southern Alps. Prior to the DXC upgrade the tunnel stretch had to be electrified. I'm not from New Zealand, but I was inspired to build this loco after I had the opportunity to spend a few weeks there in March 2019. It's a beautiful country with some amazing scenery to see by road or by rail. If you haven't been, you should go! Previously, the only custom train builds had been in 6-wide and were based on the old 9v trucks and motors. So this was a big change for me. I had never used PF motors before, never had done much with technic even, so building the trucks and drivetrain took the most time for me. I started by looking at blueprints of DX locomotives online and dragging a scaled version over a Lego graph paper template in MS Publisher to get a 1:48 scale view. (http://studs.sariel.pl/ was really helpful for this as well!) I then did most of the build in Stud.IO, building a couple test trucks along the way to test out the length on R40 curves (which are all I have right now). After ordering parts I still made plenty of tweaks as I built - probably 25% of the loco is different in some way from the digital model I built. I realized I should have 2 L motors for traction, but I haven't ordered the second one. There's just enough room for the 2nd motor with an SBrick and a 9V battery (maybe 2 - space is tight!).

I'm also just getting started designing trains in 1:48. I was designing in 6-wide, but seeing models from the guys at BMR, Brick Train Depot, etc. convinced me to think bigger. To add on to @supertruper1988's comment, @Sariel has another tool for converting measurements that I've found even easier to use in my experimenting: http://studs.sariel.pl/. If I have a schematic like yours, I'll put in the overall length of the train and convert it to studs in 1:48 scale. I've made a Lego graph paper template, over which I then superimpose the train schematic (with a transparent background) and scale it to the length I computed in the studs converter. Just like that... Lego train blueprints. That might sound more complicated to you... at the end of the day I think it's best to just figure out what works best for your personal design process. I'm still finding my way that I like best, but it's a fun process experimenting! One other thought, I remember reading somewhere (maybe in "The Lego Trains Book by Holger Matthes" - awesome book!) about picking a limiting design element to base your scale model off of. For a steam loco this might be the largest wheels (though there are a lot of 3rd party big wheels out now). You wouldn't want to design everything to scale and then realize your wheels will be too small to look right, for instance.