Electrical Problem - I think

Model Railroader Layouts and layout building
1

Hi there - I’m hoping someone smarter than me can help me figure out my conundrum. I have just built a reasonably large layout (two tracks of approx 10m - 30feet - each) made of Hornby set track. I have two sections that allow trains to change tracks, and have wired appropriately with insulated joiners in the correct places and have avoided running current into the frogs.

I use three engines on the layout, a little Hornby Thomas the Tank Engine, which does very well on the circuit, and two larger locos, a Hornby A1 Flying Scotsman and a NSW 80 class.

It is with these two larger locos that I am having problems. For both of them, they will do three to four circuits (sometimes a few more or a few less), but will then slow and stop. If I turn off the controller (a standard 1 amp Hornby controller - R965) and wait, it will start and run briefly before stopping again. The longer I leave the controller off, the longer run I get, but usually no more than 5-6 circuits.

The whole layout is nailed down onto the base board, the track is brand new, and is tightly joined. I thought it might be the controller overheating, but someone reminded me that a thermal cutout would stop instantly, rather than the gradual slow down and stop I’ve been experiencing.

Anyone have any ideas about the cause and a potential solution - I would be very grateful.

Many thanks

Anton
Brisbane, Australia

2

I would suspect that you aren’t getting enough voltage out to the track. A 1-amp controller is pretty small. Are you using heavy-guage wiriing to the track from the controller, and do you have a power bus with multiple feeds, or just a single pair of wires to each loop?

From your description (which is excellent, by the way. Lots of good info there.) I think that Thomas runs fine, because it’s small and doesn’t tax the system. The big guys, though, are running at the edge. If they don’t get enough voltage, they will heat up, and that might cause the motors to bind. When you shut down, the motors cool off and will run again in a few minutes.

As an experiment, try running one engine until it stops. Then take that one off the track, and try running the other one immediately. If my theory about overheating engines is correct, then the second engine should run well for a few laps. If it won’t run, the the problem is in the controller. In any case, if you are planning to run both of those big engines at the same time, you will need more power.

3

The thermal cutout on the controller would not work if the engines themselves were starting to oveheat. You did not specify how the the controller was connected to the layout. Is it connected in one place or do you feed the layout from bus wires attached to every three feet (1 meter) of track? If the controller is connected to only one or two sections of the layout, there will be a voltage drop as you get further away from the controller. Motors are power rated. This means that if they experience a voltage drop, they will draw additional current to make up the diference. Since current flow rate affects the temperature of the engine, the added current will cause the engine motor to gradually heat up. This, in turn, causes the the components to expand slightly. This expansion may be creating a bind that slows the engine down. Even if there is no voltage drop around the layout, the motor will still warm up from normal operation. Make sure the engines have been properly lubricated. This will eliminate or reduce the binding. The reduced friction will allow the engine to run cooler and sustain that lower temperature.

4

I’ll step out on a limb here and say it’s the power supply. I’m guessing that it’s overloading, the voltage is sagging on the system, and that just maybe it’s overheating.

Do you have access to a voltmeter? Watch the track voltage (or power supply voltage) as your little tank engine runs aroiund the track, and compare it to when one of the larger locomotives run around the track. If the power supply’s doing its job, the voltage performance should be similar. If the power supply’s running out of gas the results will be quickly apparent.

Good luck!

Mark in Utah

5

Anton,

Let me suggest a different problem you might be having. Are the engines properly lubricated, especially the armatures of the motors? What you describe seems to be more along the lines of the motors in the engines getting hot and binding due to lack of lubrication. The longer the transformer is off, the more time they have to cool and the longer they run the next time you try. Since Thomas runs fine, I don’t think it is electrical. Take the shells off the engines and lubricate the moving parts, especially where the parts contact something, with transmission fluid. Don’t use oil. Use just a tiny drop on each location, and make sure to put it where the shaft of the motor passes through the bearings on the end of the motor housing. I bet this fixes your problem.

Mark C.

6

Are you saying running the two large engines at one time is the problem or just one at a time? Some controllers (power packs) use thermal limiting instead of circuit breakers for protection. As they heat up the output voltage is reduced to limit the currrent to in your case one amp. Take the load off and the circuit is restored. How much current do your engines draw?

7

My best guess is the power supply. Same reasons as described above. Check it with a volt meter or amp meter. If you have an inductive amp meter (one that hooks around the wire) that is not sensitive enough make a loop of ten wires and hook around that. Move the decimal point of your reading one space to the left.

8

Anton
Are you running lighted passenger cars? Some cars draw more current then the engine.

9

Thanks very much everyone for your replies. I’m a newbie and so much of this is stuff I would never have even thought of. I’ll try a few of these things out and see if I get a better result.

To answer the questions of a few, I had only connected the power at one point of the track, and I was testing without passenger cars. I was initially using the Hornby power clip system, but this was quite poor as the power connectcors seemed to be losing contact with contacts in the clip.

I visited my local hobby store, but they didn’t have anything like the knowledge of you guys. Anyway, they sold me some Atlas terminal joiners, which are such a great idea, so I cut off the little power clip joiner from the Hornby controller and soldered the new terminal joiners on. This significantly improved the layout from providing one or no circuits, to the five or six max I mentioned above. But then the problem would occur as I’ve noted.

The binding seems to be exactly what is happening. Both engines are brand new, but I had heard that the lubrication can dry out from sitting in storage.

mcouvillion - you mention not to use oil - what do you recommend instead?

I’ve bought some heavier gauge wire as feeders, as well as some more of the terminal joiners, to allow me to have three separate power connection points (ie every 3 meters of track). I don’t intend to run more than one loco per track (ie max two on the layout at any one time), but I’m still wondering whether the 1Amp controller is just too small for the job (oh, I should note I have a separate controller for the inside and outside circuits).

I’ll give these things a go, as well as testing MisterBeasley’s suggested experiment to see if that helps at all.

Many thanks again to the informative replies, it’s great that people are so willing to help a newbie.

Cheers

Anton
Brisbane, Australia

10

Anton,

I recommend transmission fluid rather than oil. Transmission fluid won’t gum up over time, oil will. You don’t want to have to come back in a year or two and spend a couple of hours cleaning the the gum out of your engine, do you? I don’t. I’m a chemist and member of SAE, the guys who spec out the lubricants for cars. You’ll do better with transmission fluid. Try it. You can get a quart for just a couple bucks and it will last you forever.

I still think your problem is tight clearances in the motors and lack of lubrication. As the brass bearings get hot, they expand and bind the armature shaft, which is steel. The two metals expand at different rates when they get hot. Lubrication will help keep the temperature down.

Mark C.

Mark C.

11

I’ll give that a go. Thanks for the tip, Mark.

12

Now, just to throw a spanner in the works, I have finished introducing new terminal joiners, so there are now three (one about every three metres - nine feet) in total.
However, there has been no change to the problem.

I did try MisterBeasley’s suggestion of immediately swapping the loco that stopped with another one, only to find that the new one barely started at all, when swapped over. Also, Thomas has now developed the same problem, although it does about twice as many circuits as the larger engines before stopping.

This seems to suggest that the controller is underpowered, does it not? Does anyone have an opinion on whether a 2 amp controller would do the trick? Plus any recommendations on a particular brand/price?

Thanks again

Anton
Brisbane, Australia

13

Hello Anton! from your latest test, I do think that your 1 Amp Hornby controller is not adequate. A 2 amp unit would probably be ok, but if you can get one with more power, do so.
There are not many high power controllers, but two that come to mind are
both from MRC (Model Rectifier Corp.). First is the Trainpower 6200- total output is 60 watts-- about 2.5 amps train power(12V DC)+ AC accessory power
MSRP 125$ (US)
Second is their top model-- the Control Master 20-- total output 100 watts-- well over 4 amps train power(12VDC). MSRP is 199$ (US).
MRC also made other power packs- the Sound & Power 7000 is one,(comprable to the 6200) usually can be found at reasonable prices on my favorite online auction site(the one that starts with E*). I did a little checking this AM(us time),and found several Control Masters & a couple of 7000’s too, all at pretty good prices.
I don’t know if Hornby makes comparable units, (I don’t even know what your standard AC voltage is) I would try to find a Hornby unit first, then go hunting for one of the MRC units. Hope this helps you!

14

Many thanks for all of the advice I received. Based on the last post from willpick I bought a new dual controller which is 2 amps and 27VA. If anything was going to do the trick, this was it.

Well I’m pleased to say it worked a treat. Both lines are working well with all engines.

Now I can move on to the scenery.

Many thanks again for the words of wisdom. It was your collective wisdom that helped me nail the problem.

Cheers

Anton
Brisbane, Australia