GE AC4400CW /w CSX livery in 7 wide [WIP]

[codefox421]

[snip]

As for the loss of traction, I thought the same thing at first, then I considered that the stock 9V train motors have metal wheels too that ride on the inside edge of the track. These O gauge wheels ride on the top of the track, which greatly increases the contact patch. The locomotive is also quite heavy because of the 2 L motors and especially the AA battery pack. I've tested it pulling my 6 car Horizon Express without issue. I'll test it more this weekend when I get my 7W rolling stock back from the LUG trailer. I'm hoping there's no problems :D The plan is to make a twin unit to accompany this one.

Citing the 9V train motors for having metal wheels isn't particularly valid. They have traction rubber bands where they meet the top of the track and, while the metal portions do make electrical contact with the inside edge of the rail, those parts are spring-loaded so don't bare any weight.

That said, I think you may be right about the extra engine weight helping create traction in this case. I suppose you will know for sure once you get your rolling stock.

[LEGO Train 12 Volts]

This work is absolutely impressive!

Great project and amazing building technique!

[legoman666]

Citing the 9V train motors for having metal wheels isn't particularly valid. They have traction rubber bands where they meet the top of the track and, while the metal portions do make electrical contact with the inside edge of the rail, those parts are spring-loaded so don't bare any weight.

That said, I think you may be right about the extra engine weight helping create traction in this case. I suppose you will know for sure once you get your rolling stock.

You might be right, I hadn't really thought about it. We shall see!

[legoman666]

I weighed the locomotive before having lengthened it; 2lb 4oz / 1.04kg. Ran a test with test steel wheeled bogies, see below :) The consist is 8 cars, all 7 wide, 6 of which are quite heavy.

I've also finished my longer bogies that'll be on the final model. They're based off the instructions in Railbricks issue 6. I have regular train wheels on them for now, but they're already wired up and ready for the steel wheels. The middle set is a dummy sliding axle. Front truck will pick up power from the right side of the track. The rear truck will pick up power from the left. Bridge rectifier will maintain correct polarity. DC-DC converter will keep the Bluetooth controller happy with 10.8VDC. AA battery box is protected by a schottky diode and will provide backup power. 1L motor powers each truck. A 40mm fan keeps it all cool.

Ignore the fabulous colors :)

Still need to add another 4 studs in the middle section of the loco. I already lengthened the platforms at each end by 1 stud, so by the time I'd done, it'll be 48 studs long, up from 42 earlier.

[dr_spock]

Great looking build. I like how you got the AA battery box to fit in there. Nice use of flowers too.

[zephyr1934]

It just keeps getting better!

[legoman666]

I had to completely break it in half to do this.

Still missing that last clip at the top.

Takes curves and switches no problem.

Making it longer let me make it a lot stiffer. Found a good use for a 6x6 tile. 48 studs long now.

[jtlan]

This is looking great! Have you been able to test it on 9V track yet, where you might get less friction than on the PF track?

Where'd you get the wheels?

[legoman666]

This is looking great! Have you been able to test it on 9V track yet, where you might get less friction than on the PF track?

Where'd you get the wheels?

I'm still waiting on my custom wheels with technic axle holes to come in, should be some time this week. I've tested the the same wheels with round axles (held gears to the round axle with hot glue) and it was able to pull my train no problem. My only concern with the new wheels is that the flange is slightly different and will only work on switches if the wheels are perfectly spaced. The wheels are from here: http://shop.osorail.com/product.sc?productId=2927

[cgarison]

Really nice work on the locomotive. Based on the video you uploaded of the engine going around the track, my L-motor mule is running at the right speed as I prepare to build my latest MOC. Thanks for all the wonderful information in the thread.

[LEGO Train 12 Volts]

Everyday this work grows better and better!

[legoman666]

Ran in to traction problems when the center axles were taking most of the weight. I replaced the center axles with tubing and let them float in the axle hole. Even with the fix, it still doesn't have near the traction of stock Lego wheels though; it slips when pulling more than 4 or 5 wagons. Apparently conductive elastomer rubber o rings exist and I'd like to get my hands on some. Can't really find any that are commercially available though.

[zephyr1934]

Could you use one axle per truck for power pickup and the other two for traction? Presumably internally tying the input power lines from the two trucks together so that you do not hit any dead spots in the track.

[TheLegoKing]

Will you be doing vynl stickers for the decals?

[legoman666]

Could you use one axle per truck for power pickup and the other two for traction? Presumably internally tying the input power lines from the two trucks together so that you do not hit any dead spots in the track.

Unfortunately, due to the way the bogies are geared, the drive gears on the axles are on the same side of the truck. The gears block the pickups from being mounted next to them, post 29 has a picture that explains better than I can. So each bogie can only pull power from one side of the track. Currently trying to get some conductive rubber orings or strips.

Will you be doing vynl stickers for the decals?

I have some Microscale O gauge water slide decals I will be putting on. I bought the incorrect decal kits at first, they were for the new dark blue/yellow paint job rather than the old grey/blue/yellow scheme. They don't sell exactly what I need, so I'm going to have to combine multiple kits.

[jtlan]

Unfortunately, due to the way the bogies are geared, the drive gears on the axles are on the same side of the truck. The gears block the pickups from being mounted next to them, post 29 has a picture that explains better than I can. So each bogie can only pull power from one side of the track. Currently trying to get some conductive rubber orings or strips.

Sadly, conductive rubber usually isn't very conductive. Could you put ordinary O-rings only on the non-pickup side of each truck?

[legoman666]

Sadly, conductive rubber usually isn't very conductive. Could you put ordinary O-rings only on the non-pickup side of each truck?

The data sheets I'm reading show very low resistances. I asked a couple companies for samples. We'll see if any respond. I just gave regular rubber bands a shot but the shape of the wheels cause the rubber bands to come off quickly (within 20 seconds). The wheel isn't flat, its sloped outward. I'd need to put a groove in each wheel so the rubber band would stay put. I supposed I'd have the same issue with conductive bands too.... One company I contacted sells sheet rubber with an electrically conductive adhesive backing.

[legoman666]

Traction actually isn't too bad. That bridge it slows down over rises 5 plates over 3 track lengths from the surrounding track.

[Rail Co]

Looks like you got some Great haulage and torque abilities with that model! Great Job!

-RailCo

[legoman666]

Looks like you got some Great haulage and torque abilities with that model! Great Job!

-RailCo

Thanks! The weight sure helps. That's 1.21kg for you metric folks.

Edited August 23, 2014 by legoman666

[legoman666]

Finally applied some decals.

I guess it's done. Not terribly happy with the exhaust stack, but can't think of any alternatives.

[dr_spock]

How about the new style jumper plates upside-down for exhaust?