hoeij

I don't like the title of this thread "kids and trains don't mix". Of course they mix. Having kids enjoy the trains is great. If something breaks, who cares? As long as you still have all the pieces, it's no problem to put it back together.

I have repaired a couple 12V motors, so I'm interested to try if I can fix that 1 not working engine. How much would it cost to send it to the US?

If you avoid the highest speed settings then there is little risk of damaging the 4.5V motor. Even the highest speed setting, which I would avoid, will do little damage to the motor. At the highest setting, there would be more than 4.5V on the motor, but it would still be well below 9V because a small 9V battery simply won't be able to produce 9V under this load. To really kill the motor, you need to pull a 10 feet long train with this one motor, under 9V, and do that non-stop for a whole day (yes, I tried that, and I did kill a 4.5V motor that way. Note that a replacement motor costs only $4). The 9V battery won't be able to deliver the current to kill the motor. I don't see any risk here.

Unnecessary quote of entire topic removed by moderator. You could only use a dead 12v motor if you remove the DC motor that is inside of it. More convenient would be to use item bb53 on bricklink. The trouble with this idea is that the 12v contact points won't be able to pass 9V/RC switch tracks. Also, you would have to put the 12v conducting rail along the entire track. If you have them on only a part of the track, and you go from the part with no conducting rail to a part with conducting rail, then the train will get stuck because the 12v contact points won't be able to slide onto the conducting rails. In other words: this will only work if the train moves only on 12v track.

If you press the red stop button, and if the front locomotive receives the signal but the rear one does not, then the front of the train stops and the rear engine will start pushing cars off the track (off the table, onto a concrete floor). That's why I prefer putting both motors in the same engine.

Thorsten, Does the lego PF receiver have a rectifier, or does it only work when the polarity is correct?

I thought that the time-out was after 2 hours? Are you sure the train is moving for more than 6 hours? That's twice as long as the Emerald Night. I agree.

Sjaak, how many train cars do you have that you can put behind it? There are a few other issues to consider too: alkaline AAA batteries really aren't strong enough to pull a long train powered by 4 PF train motors. With high-drain applications, most of their energy content gets lost, and your train might only run 10 minutes or so. In high-drain applications, recheargeable batteries last much longer. You can see in this graph: http://site.greenbatteries.com/documents/alkaline-vs-nimh.jpg that if you pull 0.5 amp out of AA batteries, then only about 1/4 of the batteries energy content will actually come out as electricity, and the rest will be lost. Rechargeable batteries do better under this high load, they lose less energy so they last longer (even if their initial energy content was lower). In your experiment, say 2 engines and 20 cars, you'll be pulling 0.8 amp (more if you add more cars) and you're pulling that not out of AA, but out of AAA batteries (which obviously can handle much less than AA's). If you use alkaline batteries, you would be way overdrawing them, rapidly killing the batteries. Your train might run for only 10 minutes or so (again: rechargeable's will last longer). Also, given the limits to what the 6 AAA batteries can deliver, I suspect that with 1 battery box, a train with 3 PF motors will actually have more pulling power than a train with 4 PF motors. If you really want to power 4 PF motors with 1 battery box, and actually get more pulling power than you would have with 3 PF motors, then you'll need to use a LiPo battery, like the lego 8878 LiPo. This LiPo will deliver the amps that you need with no problems. It's not only stronger than 6 AAA batteries, but even stronger than 6 AA batteries (a lego technic excavator with a 8878 will perform better than one with 6 AA batteries). With the 8878, your train, pulling almost 1 amp, should still last more than an hour.

Some of them belong to my son, the rest are mine. LegoSjaak, I don't actually have a lego city at home: there is no room for that. I get to see my layout only once per year, at the train show. The rest of the year the trains sit in the display cases, and the rest sits in boxes... You are right that getting all this stuff from A to B, and then back to A again, is a tremendous amount of work. Boxing it all up in a way that you can find things quickly during setup time, it's time consuming. There are about 20 places in the layout that have wiring, and that costs a lot of time too. There are always some items that don't actually end up in the layout at the show because I simply run out of setup time. After doing all that work I always think: No way I'm doing that again next year. But then, when it is time for the next show, I somehow forget how much work it was, and convince myself that this year, the setup won't be all that bad... Right now I think that next year I'll do a much smaller layout. But whether I still think that way next year, that's not sure. Right, and since I have no room for it at home, I figure, what good is this stuff if I don't display it at the show? Thanks. Yes, the logistics of packing/moving/setting up all this stuff is hard (the time you get in that building for setup is only about 8 hours). Very perceptive. I bought these SF cars already assembled, at the same train show a few years ago, for $15 per car (getting this excellent deal is what got me to start looking for more deals, and that's what got me into buying so many trains).

I'm a member of a train club, the BBMRA. At our annual show, I had a lego layout (I'm the only one in the club that does lego). Let me know what you think. So far, this is the only footage that I have, but I hope to get more video from other club members. By the way, the logistics of getting all this stuff there is quite complicated, boxing it all up, finding things quickly, etc. The wiring is also very time consuming. To alternate which trains are running, the blue track alone has 10 spots with wires (3 power supply, 4 remote controlled switches, and 3 interrupt rails that have wires on them). All this wiring has to go substantial distances underneath the tables, sometimes more than 10 feet, and all of that takes a lot of setup time. The two gray loops have also 4 power connections each to prevent slow-downs in parts of the track, etc. Anyways, let me know what you think.

The pulling power would be much greater than the strength of the magnets. So the length of the train you can pull depends only on the strength of the magnets, and does not depend on the strength of the 4 PF motors. To put it another way: If you use just 1 engine, with 2 PF motors, then that will be able to pull just as many cars (unless you decide to strengthen the couplers of course). If you want to use two engines (the first with 2 PF motors, the second with no motors) then pulling this dummy engine is about as hard as pulling 8 Maersk cargo cars. But you can drastically reduce this load (discussed in another thread). At our train show I had a train with 2 Maersk engines and 8 cargo cars. This train had just two 9V motors in it (which are about equally strong as the PF motors, certainly not stronger) both of them in the front engine. This train ran fine on speed setting #2 (which is only 4.2 volts) (at least, it ran fine after cleaning the track). In other words, this 10-feet long train was a mild load on the two motors, because the train already moves in the second-lowest speed setting.

That was also true when I bought my 7745. I completely disassembled the train, then hand washed the pieces in soapy water. That made it look much better. For the discoloration, my white bricks were discolored on only one side (the side of the brick that had been on the outside). Simply putting them in the other way around solved the discoloration problem. My 7745 also came with 1 extra car, and, at an excellent price. I added two more cars (the pieces are not so expensive on bricklink) so it is now 6-long. This did require using 9V wheels, the 12V wheel sets have way to much friction.

There are some other benefits of ME track that probably haven't been mentioned yet. Last weekend I had a lego layout at our local train show. I had a long 12V loop and a long 9V loop. The 9V track has less metal than the 12V track, so the 9V track has more electrical resistance, and so you have to supply power to more spots on the track. In one long loop, I supplied power to 4 places. Two of those places were 9 feet away, one of them was 16 feet away (this means crawling underneath the tables to get those wires to where they need to be). Setting up all this wiring adds a huge amount of time to the setup time. With ME track (which I do not yet have) you have all metal track, so you have much less electrical resistance, and so you have to supply power to fewer spots on the track (perhaps 1 spot would have been enough?). That would have saved time during setup. Has anyone measured the electrical resistance of say 100 track lengths of ME? (for 9V that's 8 Ohm if you count it back and forth).

I too think that it is very unlikely that lego will discontinue PF. It's used not just in trains but also in lego technic. Lots of things are designed for it. I think it is almost certain that lego will continue to sell PF for years to come. After all, they've invested into it, it is selling well, so why not continue to make $ on it? These items are so popular that they are sometimes in short supply, and temporarily unavailable, and that probably lead to rumors. But rumors, that's all that they are.

I don't know the precise count, but for my upcoming train show I remember adding up their lengths. The 14 moving trains add up to 83 feet (there will also be a few stationary trains but they are short so they don't add much to the total). Not all will be running at the same time, typically I'll have 6 running at the same time (more is possible if I have the time to watch them all) (this is on 4 loops, the loops that have more than 1 running train need to be watched).

Only the ones with the technic axle and technic bricks. The other wheels in the RC train sets are good.

You can run the train with just one of these battery boxes. The PF system will work fine on 4.5 Volt (of course, the top speed will be lower). (In my 7939 I use only 4 AAA batteries. Works fine. The reason I only use 4 instead of 6 is because this lowers the top speed, and that prevents it from accidentally derailing and falling off the table. I have not tested it with 3 batteries, but seeing how it runs with 4 I'm sure that it'll be fine with 3 too).

Personally, my favorite "12V" trains are several of the locomotives from the hobby train box 10183. I'd clean everything (if it looks clean, it's no guarantee that it's actually clean. It's clean when the track cleaner won't take anything off anymore. It doesn't matter how it looks like). The train will start to run smoothly after you cleaned the track and ran the train a couple of loops. For the traction bands, there's someone on eBay listing them for $0.85. Those ones work well (thin bands work better than thicker bands. You want thin traction bands, then the train sits a little lower, which makes it go better through the switchpoints without derailing). I once bought a 12V motor where someone had rubbed the electrical contacts with sand paper. Never do that! (don't think that they have to look clean, that doesn't matter). On the 12V track, I like having cargo trains that run slowly and at constant speed. This works better in 12V than under 9V.

You can if you want to (I tried out my blue 12V power supply, it has no problems with three 12V train motors. I'm sure the same goes for the gray one too). For a large track, you need a multimeter to check for bad connections. If you have a 100 track piece 12V loop, there should be litte slowdown *IF* all connections are good. For a 150 track piece loop, I use only 2 leads (that's for 12V track, for a 150 track length 9V track I would use 4 leads). For your 100 track piece loop, you have a total of 200 connections (2 per midrail). If even one of them is bad, you can have a pretty big slowdown on the track. A multimeter is very helpful to find it. When you insert one midrail into the next one, sometimes you feel no friction on one side, that is potentially a bad connection. If you give the female connector side a bit of a squeeze, then insert the next midrail, if you feel some friction (on both sides) when you put it in, then you know you'll have a good connection again. If you have a relatively small loop, and if you have a bad connection in one spot, then the electricity can simply go around the other way, and the train runs fine. But if you have a long loop, then the electrical path (to go around the other way) becomes too long, so that one bad connection leads to a big slowdown (i.e. voltage drop) in certain parts of the track. So for a large loop, all your connections (two per midrail) need to be good (either that, or you have to add more leads). How long is your loop? If it's less than 100, and if you see slowdowns, then all you have to do is to find and fix the bad connection. For longer loops, I don't use the lego connectors to connect to the track. I just connect the wires straight to the midrails (you can connect them at the bottom, you can bend open those clips, insert a wire, and bend them closed again). This way it's easy to have as many leads as you want. I use 20AWG wires (has a little bit less resistance than lego wires, so you can cover some distance without losing much volts). Go to a hobby store and buy some track cleaner. Helps a lot. Don't worry about rust, or other visible imperfections. Those things don't matter. It's the dirt that you can't see, that's what's blocking your electricity. Put some track cleaner on a cloth and clean it. Keep cleaning it until you see no more dirt coming off (for some reason I don't understand, you can see the dirt when it's on the cloth, but you can't see it when it was still on the track).

If you run all your trains as PF trains, wouldn't it make sense then to sell the 9V stuff and buy all PF stuff? A 9V motor costs a lot more than a PF motor. Moreover, the PF train motor is a bit more efficient than the 9V train motor, and will probably last longer too (I've had one or two broken 9V motors, but I haven't heard reports of broken PF motors, so PF motors may be sturdier than 9V motors). All combined, even if you have 9V motors, it's more economical to sell them and to use PF motors in your PF trains.

What do you end up using the most? 9V or PF?

You can also make a custom battery "box" that will fit in the 2-studs wide area. Take a PF cable, cut it, and wire it together to 4 AAA batteries (make sure to get the polarity right). The advantage of using 4 instead of 6 AAA batteries is that this way, the train won't derail at the top speed setting (I don't like having a top-speed that can make the train fall from the table to the floor). Four AAA batteries is enough to reach a speed that is higher than what you'd want for a cargo train (I've tested that, I'm using only 4 AAA batteries (plus a few wires) in the battery box of my 7939 cargo train. The pulling power is the same as with 6 batteries. The top speed is of course lower, but I think it's better that way, and in my view the top speed with 4 AAA batteries is still higher than the speed I want to run this train at). These 4 batteries (without the battery box) would also fit in the BNSF engine, but you'll have to be a bit creative to wire them in series. The PF controller, that may be trickier. By the way, if someone manages to produce a sticker that accurately matches the BNSF colors, then that would be very nice and I'm sure several people would want to have those stickers.

Suppose you have a PF train, and suppose it is a cargo train that you want to run slowly, say at 4 Volts (that's fairly close to speed setting #2). So you want your train to run at the speed of 4 volts, however, the batteries deliver 9V. My question is, the energy in the remaining 9-4 = 5 volts, where does it go? This has to be dissipated somewhere in the form of heat, but where? Does this happen inside the motor? With the 9V system, this excess energy (the energy that needs to be wasted to go down from 9V to the desired voltage) this energy gets dissipated as heat inside the 9V controller (that means that if you choose a low speed setting for your 9V train, then the 9V controller will get warmer than it would at a high speed setting). But with PF, the PF receiver is small, so it can not dissipate much heat. The only other place I can think of where this excess energy can be dissipated is in the motor. Question is, is this true? (if so, then a train motor powered by the PF system should get warmer than the same train motor powered by a 9V train controller). Has anyone compared that? Also, if this is true, then the PF train motor should get warmer at low speed settings than it does at high speed settings. Has anyone observed if that is true?

That's right. Note that to do this measurement, it was necessary to cut a 9V connection cable so that I can insert the multimeter in the setup (this was OK, I had to cut some connection cables anyway to make them longer with additional wiring. Lego 9V wires are 22AWG, but when I make them longer I insert 20AWG wire to minimize losses). You can see on: http://www.philohome.com/motors/motorcomp.htm that if you change the voltage while keeping the torque constant, then the current stays also almost constant (within 10% or so). So the current is nearly independent of the voltage. I observed the same thing in my measurements as well. That's why I focus on current, not on volts or watts. Another thing I found in my measurements is that if you add cars to the train, cars with equal weight, then each additional car increases the current-consumption by the same amount. So if you've measured the current for "engine", "engine + 2 cars", "engine + 4 cars" then you can predict (with good precision) what the average current will be for "engine + 6 cars", or "engine + 8 cars", etc. Again, this behavior is in good agreement with how DC motors are supposed to behave.

Thorsten, what I want to know is if the battery or the Lipo lasts longer at low speeds than it does at high speeds, or if the battery life is the same regardless of the speed setting. My dual-motored train uses 420 mA (210 mA per motor). I measured the current, and found that it uses 420 mA at any speed setting (I tried speed settings 1,2,3,4, which is 3.0, 4.2, 5.4 and 6.6 Volts). The friction force is pretty much the same at any speed setting, and so is the current. Those are measured facts. The question is: can one compute from that how long the train will run on the batteries? The LiPo has 1100 mAh, so divide 1100 by 420 and you get an estimate for how long this train can run. If I use 6 rechargeable AAA batteries, you get a similar number. The problem is that this number is independent of the speed setting (which is a bit unexpected). Question is: at a low speed setting, will the train run longer than the computed number (1100 divided by 420)? Letting the train run for hours on end is not really an option here (it's temporarily in the TV room, there would be complaints). In some sense the question is moot now, I've decided I'll run this train with the 9V system at the train show. But this means quite a bit of wiring because the track is too long to supply power to just one place on the track. To make sure that the power is evenly divided over the track, I've cut three 9V track connectors and added wiring to make them 10, 10, and 16 feet long. I did this because I thought (dividing 1100 by 420) that the train wouldn't run long enough in the PF system and I'd have to replace batteries too often. But I don't actually know how long the batteries would have lasted.