legoman666

Watching the Allegheny take turns mesmerizing.

Love the doors. Can it take curves?

I dont think you understand how amperage works in simple DC motor circuits. If the max current is listed on the transformer as 2A, that doesn't mean it's going to output 2A. For any given scenario, the current will vary depending on how much resistance there is on the motor and how fast it's spinning. As a lightly loaded DC motor turns, it generates a backwards-flowing electromotive force that resists the current being applied to the motor. The current through the motor drops as the rotational speed increases, and a free-spinning motor has very little current. It is only when a load is applied to the motor that slows the rotor that the current draw through the motor increases. (some quotes from wiki because I couldn't figure out how to word it elegantly) For example, say we're running a regular 9V train motor at full speed (9V) with nothing attached. No cars, nothing on top of the motor, nothing. The motor will generate back EMF which will drop the voltage across it by... say 5V. Lets make up a number for the internal resistance that this motor has, say 25ohms. (9V - 5V) / 25ohms = .16A. Now say we build a locomotive on top of the motor. This will increase the resistance the motor encounters and will reduce its speed. By reducing the speed, you also reduce the back EMF. Say the back EMF falls to 2V which will increase the voltage to 7V instead of 4V. Then we have 7V / 25ohms = .28A Now say you hold the motor still with your hand as you turn the knob on the controller to max. There will be no back EMF and the voltage across the motor will be 9V. 9V / 25ohms = .36A Stalled motor = max current, motor by itself zooming around track = minimal current. The current being drawn is completely independent of the DC power supply (as long as it can provide enough). You could use a car battery, which is capable of supplying >100A, but would still only supply 12V / 25 ohms = .5A for our hypothetical motor. Remember I made up all of my numbers, but the same thing will happen in real life. So to answer your question, keep the voltage down between 9V-10V max, and you will keep the current down. 15.6V / 25 ohms = .6A, whereas 9V / 25 ohms = .36A. Hope this helps, I'm an electrical engineer. This is what I do.

I extended the middle car by 4 studs to fit the PF battery box and IR receiver. The green bus from the same set donated the extra windows since I didn't have any in that color. Just barely makes it around the curves, but has no problems with turns or switches! First time I've used the clips on the side of the motor... I had to remove one set of wheels from the two lead cars in order to take turns smoothly. Both the IR receiver and the battery box are offset half a stud. If only the PF wire connectors were smaller... Luckily sticking out the side of the car 1/2 stud doesn't cause any problems with the turning. http://www.youtube.com/watch?v=fTp4a8sjOUo So for my question, has anyone successfully added a PF polarity switch mounted on the side or bottom of one of the cars so that the tram can automatically change directions when it gets to the end of a one way rail? I'd love to be able to fit it on the middle car so I don't have wires going between, but I don't think there's any room.

My LUG has a different way to recycle failed 9v motors: pull the motor out of the 9v assembly and solder in the leads for the charger of the rechargeable PF battery pack. Use it on 9V tracks with the controller turned all the way up. This way, you can use cheap PF train motors that are pulling power from the rechargeable pack which is being constantly recharged by the 9V rails. It can even go over non powered track sections. It will run forever which makes it great for shows.

Looks great. Don't be discouraged, you asked for comments, you got comments.

Serenity from Firefly. Not my own design.

Booster's coming along nicely. Starting to run out of grey bricks...

Well done, very authentic. What does the bottom look like?

Don't forget to share what method you use to remove the paint from the road plates ;) I'm planning on making one of these too.

Updated the front of the engine. Looks a lot better. Working on the booster now.

I hadn't even considered those. I might look in to using them for the passenger cars. They don't have fans so using em won't hinder anything. I've been using these: http://www.bricklink.com/catalogItem.asp?P=6081 at a cost of about $0.85 each in bley. Thanks for the info! I have a few items in my cart at Shop@home that need ordering anyway.

Thanks! I'm working on the 2nd car now, the cabless booster (I had to look up what it was called). I will also shorten the cab by about.... 1 brick hopefully. It will take a lot of work though. I just ordered the 1x4 curved roof pieces to make the booster and a few cars. I will post pictures when I have them

http://www.bricklink.com/catalogItem.asp?P=60481 might be a good piece for the trim between the windows. Not sure if it'll fit; I'm not at home.

Thanks! It was the only way I could think to do it on an 8-wide. The windshield on the Lego official set runs about $20-30 on Bricklink. I don't like the red pieces I have in front of it. Doesn't look smooth enough.

Hi all, First train MOC since I got back in to LEGO about 1.5 years ago. Finally got the space to do a permanent layout in the basement. Just need to set up some tables or make a workstation. Here it is! I redid the cow catcher at the last second. I changed it from 6 wide to 8. Much better this way. Allowed me to curve it more gracefully. Not happy with the headlight. I couldn't decide how to make it better though. It needs to be bigger. I didn't know I had so many 1x2 light grey grills.... I'm thinking the cover over the rear door needs to be raised a little to bring it closer to the roof. The windows took some SNOT work to get right. They're a little high on the chassis, but changing them would require tearing apart the whole thing. This engine is like... enormous compared the rest of my layout and trains. It completely dwarfs everything. If you open the door in the back, there's a little 9v battery box that powers.... An M-PF motor that turns all 4 cooling fans! All they need are some decals. That's all. Rolls around turns pretty nicely. It's a bit heavy though.

Looking to replace the plaque on my 7181 UCS TIE Interceptor. Used ones already applied to 1x8's are ~$40 on Bricklink. I did a Google Image search with a file size restriction but didn't come up with anything useful. Does anyone know where to get a nice image to use? I'd even paypal someone to provide a high res scan if that's what it took. I have sticker paper to print on.... just need an image to print.

I just bought 2 of the sets yesterday. I built one yesterday and will build the other tonight. Are there any MOC instructions or designs for redesigned internals for the two passenger cars so I don't end up with 2 of each? Like maybe a sleeper car or something?