New to 9v trains... or trains for that matter

[Hobbythom]

So I just bought a 4558 Metroliner for a sweet price (€125 including box) and now I am looking for things that are must-haves when you are starting with 9V and things that one absolutely needs to know. So all you experienced train techs, what are your pro tips? Thanks in advance!

[JopieK]

Good to here that Hobbythom. Not a bad deal at all! Depends on what your plans are of course. You can go as far as your fantasy goes :)

[Hobbythom]

Well it just that I am curious about the speed regulator, cleaning and maintanance and such.

[fred67]

I haven't had to do any maintenance on my trains (aside from the occasional dusting). Motors do go bad; I've even had some bad track that, even after cleaning, still didn't work well.

You can get the speed regulator on BL, but I'm wondering if anyone's tried a speed regulator from another model train company. I know the voltage needs to be right, but I've always disliked how "steppy" the LEGO regulator was anyway.

9V track is expensive; if you haven't been in the train forums until now, you should take look at ME Models, who are manufacturing after-market compatible track; the problem is that while they are in the process of delivering plastic track from their kickstarter project, they haven't released any metal ones yet. They previously had made compatible track that I was lucky enough to get at the time, and it worked well except for the occasional conducting problem from some no-so-great connections, although on a nice, level table, they worked just fine for me.

I could really go on and on about it... you got a really nice set, there, Hobbythom, but there's a lot of 9V trains you could add to your collection. I really think, though, that unless you're happy with a small oval, you probably want to expand your track.

[JopieK]

"I know the voltage needs to be right, but I've always disliked how "steppy" the LEGO regulator was anyway." if you open the regulator you see why: they literally use steps!

Also see the discussion here.

[fred67]

I know! But other model train speed regulators don't, they're continuous. I don't know why, if you're putting out 9V, any speed regulator from any model train company wouldn't work.

[JopieK]

I know! But other model train speed regulators don't, they're continuous. I don't know why, if you're putting out 9V, any speed regulator from any model train company wouldn't work.

The LEGO version also works with an LM319 so I don't understand why they did not use a regular potmeter.

The LM317 is very suitable I think (from the TI datasheet:):

• Output Voltage Range Adjustable From 1.25 V to 37 V (that doesn't mean the entire circuit can receive 37V)
  
• Output Current Greater Than 1.5 A (a bit low I think, since the train motor could draw 950 mA according to Philippe, so driving with two train motors could easily exceed the 1.5A)
  
• Internal Short-Circuit Current Limiting
  
• Thermal Overload Protection
  
• Output Safe-Area Compensation
  

The datasheet also has some circuits that could have been much better: http://www.ti.com/li...mlink/lm317.pdf

This is what the LEGO version looks like (more or less):

[THERIZE]

Lets pretend we all understand those circuits...

[dr_spock]

Maintaining 9V is not much different than maintaining scale model trains and tracks. You may have to clean the tracks and wheels and contacts from time to time if they get too dirty or oxidized to conduct electricity smoothly.

Lets pretend we all understand those circuits...

It's not too bad, following a circuit is kind of like following train tracks.

Edited July 29, 2015 by dr_spock

[Hobbythom]

Thanks for the advise everyone. I'll keep an eye open for 9v track!

Edited July 30, 2015 by Hobbythom

[Phoxtane]

At this point in the game, I'd recommend to any newcomers to just stick with Power Functions, and invest in a good set of rechargeable batteries. 9V stuff is only getting more expensive, to the point where I'm considering holding onto my 9V stuff for a good while and then selling it later on rather than use it. At the same time, there's no good way to convert PF track over to 9V, and ME Rails has been having enough issues lately with their solution that it'll be a while before I see any. I suppose if you're that deeply invested in 9V, then go for it if it makes you happy.

As for the Lego 9V transformer, is it possible that they limited the output to 1.5 amps in order to make it safer for kids? I'm just starting out in my college career but if the amperage were much higher, wouldn't it pose a safety issue to bridge the two rails with your arm or something? I'd be all for redesigning the 9V transformer circuit in order to increase available power but I'd worry about safety at this point, especially at my LUG's shows where the trains act as a moving barrier (we don't put up cordons, so we run two tracks on the outer ring of our displays as the first line of defense).

[Legotom]

The output might be limited for safety, but also for cost. Generally speaking a lower current circuit will be cheaper to produce than a higher current circuit. Cheaper components, smaller gauge wire, thinner copper tracks on the circuit board. If the trains don't need more than 1.5 amps, then there is really no advantage on spending extra to make a higher current controller.

Generally speaking 9v DC cannot kill someone, unless it's placed directly across the heart. Dry skin conductivity is somewhere in the order of 40,000 ohms - 1,000,000 ohms. So the potential current draw is very very tiny. It might be possible, but you'd have to have a very unfortunate set of circumstances to kill someone.

Edit to add: the 1.5 amp limit might also be to avoid motor burn out. I'm not sure what current draw a stalled motor could achieve, but the 1.5 amp limit might be to avoid the motor overheating and burning out under stall conditions.

Edited July 30, 2015 by Legotom

[Brickthus]

A realistic output from the 9V controller is 300mA before the voltage starts to drop under load. Other versions of the LM317 and related devices are available, up to an LM338 with 5 Amps capability (needs a big heatsink).

If your trains are much more than a single motor on a set or two then I would recommend something more powerful. I use a dual 30V 3A variable bench power supply, which has been successful for running heavy 9V trains all day at shows. It provides smooth power that 9V train motors like, as opposed to PWM that they hate. Trains folder here

In running 9V trains, stick to 200mA per motor for long running and reliability, peak at 300mA per motor.

The Power Functions train motor is much more tolerant of PWM and a bit more powerful.

The PF LiPo battery delivers 800mA so two engines with a LiPo, IR Receivers on the same channel and 2 motors each would pull all but the largest trains. My Hogwarts Express is in that league, with 4 train motors and gearmotors and lights as well; it has worked well as 9V with the bench power supply but a single LiPo was not enough. It drew 1300mA at the top of the hill. A LiPo battery is potentially more dangerous because of its low source resistance. Fast charging and discharging of LiPos has led to fire issues in laptops, Tesla cars and Boeing aircraft, some of these fixed by spacing out and cooling the cells.

I suppose a few small resistors are cheaper than a single potentiometer, hence cheaper for the 9V controller to be stepped. The circuit as it stands would need a 3kohm pot. Most are 10k, which would need a larger balancing resistor and the pair would limit the available current and need a transistor stage, hence the cost escalates. The LM317 data sheet has better circuits for a variable power supply; indeed my bench power supply is based on similar circuits, with a few op-amps and power transistors thrown in.

Phoxtane is right; barriers are necessary for trains, to avoid little fingers getting hurt. This is especially true of larger trains with more momentum. I still have a scar from being run over by my 9F steamer as I was repairing the track!

Mark

[Phoxtane]

Phoxtane is right; barriers are necessary for trains, to avoid little fingers getting hurt. This is especially true of larger trains with more momentum. I still have a scar from being run over by my 9F steamer as I was repairing the track!

Oh no, we use the trains as the barrier itself - they discourage people from reaching through with their hands, especially the smaller kids where the trains are at shoulder height. I'm not terribly fond of the practice because it limits how we can run the track through a layout (only on the outer edge), but nobody in my group has the space to store any sort of clear plastic barrier or the equipment to transport them with, and since our group is spread out across a good portion of Colorado (and southeast Wyoming) travel time starts to become a significant factor. It's a shame because we can't do anything fancy like the Texas Brick Railroad group.

What I was more worried about was somebody bridging the tracks with a higher-amp current running through them and getting a nasty shock. That's where the barriers would come in.

[dr_spock]

Clear plastic barriers are useful to keep little or big hands from knocking over the trains. One of my trains was involved in what looked like a Godzilla attack before we started using clear plastic barriers

[zephyr1934]

Phoxtane is right; barriers are necessary for trains, to avoid little fingers getting hurt. This is especially true of larger trains with more momentum. I still have a scar from being run over by my 9F steamer as I was repairing the track!

Wow, you really bleed for your ABS (grin... I probably have too). In all seriousness though, thanks for the detailed discussion on the limits of healthy motor operation.

What I was more worried about was somebody bridging the tracks with a higher-amp current running through them and getting a nasty shock. That's where the barriers would come in.

Isn't that what the little wire running around the top of the fence is for? (yuck yuck yuck)

Like Dr. Spock, I've had my incidents with little fingers and trains. At one of my earliest shows the kids would come up to the layout and rest their fingers across the tracks. Then after getting stanchions the kids will still sometimes shoot under them. At one show a kid shot under and grabbed the locomotives on this train in about 1 sec flat and crushed them to pieces. I am so scared that I can find both of those pictures in a few seconds.

For larger venues you can ask them to provide stanchions, but kids will duck under a single rope/chain. And less frequently climb between a double rope/chain. Some venues will even provide fences instead of stanchions. Though an even simpler solution is to just leave 2-3 ft of table without anything around the perimeter of your layout.

[Legoboy22]

If you want a large layout you will either have to spend alot of money or look for good deals thT only pop up every so often. But good luck:)

[Mat9vtrain]

Hi all. After owning a 4558 Metroliner in 1991 which was sold 6 years later I now, 30 years later, want to step back into the 9V Lego train topic. I found a 9V speed regulator which doesn't work (green LED is off and train doesn't run). The transformer defintely works.
I measure 11,85V AC as incomming voltage. What part can be broken in the circuit?

I measured diode D1 and D6 and compared this with the result of a working speed regulator. The values are exactly the same. Also both capacitors C1 and C2 are looking good. 

[Vilhelm22]

Deleted post

Edited May 26, 2020 by Vilhelm22

[dr_spock]

5 hours ago, Mat9vtrain said:

Hi all. After owning a 4558 Metroliner in 1991 which was sold 6 years later I now, 30 years later, want to step back into the 9V Lego train topic. I found a 9V speed regulator which doesn't work (green LED is off and train doesn't run). The transformer defintely works.
I measure 11,85V AC as incomming voltage. What part can be broken in the circuit?

I measured diode D1 and D6 and compared this with the result of a working speed regulator. The values are exactly the same. Also both capacitors C1 and C2 are looking good. 

Do you get 11.85V AC on pins of the power connector soldered on the circuit board?  From the circuit diagram, it looks like the LED should light up if there is power to the circuit board.