The need for speed (controlers)

[robc_wa]

I am putting together a sort of railcar, and have been drawing together some good ideas from folks on this forum. I have selected the Tamiya Universal motor gearbox 70103 - I believe this provides the power for a railcar on Mathew Foster's Takasaki Light Railway ( It’s also very cheap- cost about $10 shipped from Japan!)
In order to test the motor I have built a chassis on the John Rogers Flying Plank system and have tried it out on my fledgling line. It took 1 minute 10 seconds to cover a measured 10metres. I suppose that is 0.6 Km /hour or a scale 11km/hour. Fiddling with weight to give more traction didn’t help much. I have used the fastest gearing option in the Universal gearbox. By contrast my only other "real" motive power, an IP Rapier (with optimised weight) runs the 10m in 40 secs and then seems to speed up as the motor warms up!
I had thought of putting a speed controller in the railcar but this may be a bit silly. Any way – to cut to the chase - what sort of speeds do people run things at? – Yes I know - Rule 1 or is it 2!!
PS Flying Plank puts me in mind of the early German Diesel railcars the “Flying hamburger” So I like to think of it as a Fleigende Planke
Regards
Rob

[Sir Clothem Cap]

Speed is relative to the track conditions and atmosphere of a railway, What is stupidly fast on a railway that winds through a garden is fine on a relatively straight larger layout. So speed is really in the eye of the beholder and should be in character with the railway. I know that doesn't really answer your question but on some railways speed or too much looks silly where on others its perfect.

Imagine you are the scale of your railcar as it goes round does it look too slow or fast to your eye. That is the acid test.

I have seem garden railway owners getting irate because some ones train is going too fast and on one occasion too slow for the atmosphere of the railway.

[GTB]

  I have selected the Tamiya Universal motor gearbox 70103  -  ( It’s also very cheap- cost about $10 shipped from Japan!)

You can buy the Tamiya range of gearboxes off the rack at any Jaycar branch. Not as cheap as bringing in direct from Japan, but a lot quicker.

The 70103 seems to have a minimum gear reduction of about 100:1, which is far too high in my opinion. To get even the crawl you are seeing, the motor will be screaming it's head off.......

Try the Tamiya 70167, which is the same price, but has 38:1 as one of the gear ratio choices. With no other changes, that should get the Fleigendplanke up to about 34 kph (20 mph in the old money) which would be a reasonable top speed on the narrow gauge.

IP use a 30:1 reduction and 3 volts in their Ezee range. I found even that a bit slow, so I used 4 cells and fitted a simple speed control.

The advantage of the speed control is that it gives you the flexibility to trundle along slowly and quietly when you are on your own, or pottering about in a yard,but you can still cut in warp drive on large layouts, or when a rogue steam loco threatens to rear-end you.

If you can do you own electronics, I used this circuit in my railcars and the Fowler diesel, with the transistor types converted to locally available equivalents. The local Jaycar branch greet me by name these days.....

http://www.eleinmec.com/article.asp?13

If you aren't into rolling your own electronics, IP have a very simple manual speed control available and Andel have a more sophisticated one. You would be looking at the equivalent of 20-30 pacific pesos, plus postage.

Regards,
Graeme

[robc_wa]

Thanks Bryan and Graeme for your replies. It seems that a speed controller is a good thing then. I take the point about being able to get out of the way in a hurry!
I popped into the local Jaycar (only 5 mins away) and got the 70167 motor gearbox. Unfortunately it is too wide over the take off point for 32mm back-to back so it can’t go under the chassis in best FleigendePlanke fashion and it is a bit too large for the modest bonnet that I plan for the beast. However it will probably find a use in a small diesel. Experimenting now with an old but fast motor from the bits box and a standard worm drive. I have a Cambrian kit for a speed controller but the circuit Graeme linked too will do in the future.

Rob