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Wheel standards

THEPJC

Joined: 1-01-70

Topics: 2

Replies: 1

Posted: Mon 12th Aug 2013, 9:55am
Wheel standards

Hi again,

As I am new to the world of miniture railways, for my new build petrol/electric locomotive what is the maxium distance between axels for a 4 wheel locomotive still allowing it to travel tight curves?
 

Replies To This Post

johnnicholson

Joined: 1-01-77

Topics: 12

Replies: 69

Posted: Mon 12th Aug 2013, 11:29am

Can I suggest that you have a look on this website under the ABOUT US section where you will find a drawing of wheel profile track standards extra. Whe laying track bends can be gauge widened up to approx 3.25 mm but this will depend on the radius of the curve.
 

George

Joined: 27-01-10

Topics: 0

Replies: 20

Posted: Mon 12th Aug 2013, 3:33pm

I would like to suggest you look at the topic minimum gauge railways under misscelanious where you can see rose her locomotive going through 6 or 7 foot radius. If I am not misstaken the wheelbase is something like 40cm. If you like I can ask for you. Mind you she does widen a bit more and greases the inside of rail lightly to prevent squelching
Best of luck George
 

Railrose

Joined: 25-06-07

Topics: 1

Replies: 8

Posted: Tue 27th Aug 2013, 10:56pm

My petrol mechanic 'Panter' runs well with a 50 cm wheelbase, 130 mm dia wheels on my portable tracks with 1800 mm (6 feet) radius and 2 mm gauge widening. It's not the limit however, she also runs on my indoor tracks with 900 mm (3 feet) radius, but I needed 6 mm gauge widening. My wagons have standard 440 mm wheelbase and run very smoothly with 100 mm dia wheels. The bigger the wheels the more widening you need in those extreme cases. I once shunted a friend through the house, he sat on my longest wheelbase wagon with 600 mm (2 feet) wheelbase, also on 130 mm wheels. To cut short, a 2 ft wheelbase through 3 ft curve with 1/4 inch widening and 5 inch dia wheels. You'll need a little greasing to reduce friction and prevent the wheels from climbing off the track. There seems to be no substantial difference between fixed axles or when the bearings are in the wheels. Most friction turned out to be on the railhead, less than between flanges and rail inside.

Panter also runs very smoothly on permanent tracks, speeds up to 27 km/h, bigger wheels allow for smoother running at high speed, but the great dia ones on fast steam locos are all about piston speeds, compare those to Japanese or French High speed trains of the modern age. Longer wheelbases give more stability, but as practice taught me, if you want to go minimal narrow gauge you best keep it under 60 cm or 2 ft, and there's still enough stabilty at extreme speeds. Short wheelbases are better on uneven tracks, where the mutual tilt of the axles has to keep all four wheels on the track.

It must be possible to work out a formula for the relatvity of wheelbase, wheel diameter and curve radius but that's for mathematicians, not for a practical minimal narrow gauge artist like me.
My petrol mechanic 'Panter' runs well with a 50 cm wheelbase, 130 mm dia wheels on my portable tracks with 1800 mm (6 feet) radius and 2 mm gauge widening. It's not the limit however, she also runs on my indoor tracks with 900 mm (3 feet) radius, but I needed 6 mm gauge widening. My wagons have standard 440 mm wheelbase and run very smoothly with 100 mm dia wheels. The bigger the wheels the more widening you need in those extreme cases. I once shunted a friend through the house, he sat on my longest wheelbase wagon with 600 mm (2 feet) wheelbase, also on 130 mm wheels. To cut short, a 2 ft wheelbase through 3 ft curve with 1/4 inch widening and 5 inch dia wheels. You'll need a little greasing to reduce friction and prevent the wheels from climbing off the track. There seems to be no substantial difference between fixed axles or when the bearings are in the wheels. Most friction turned out to be on the railhead, less than between flanges and rail inside.

Panter also runs very smoothly on permanent tracks, speeds up to 27 km/h, bigger wheels allow for smoother running at high speed, but the great dia ones on fast steam locos are all about piston speeds, compare those to Japanese or French High speed trains of the modern age. Longer wheelbases give more stability, but as practice taught me, if you want to go minimal narrow gauge you best keep it under 60 cm or 2 ft, and there's still enough stabilty at extreme speeds. Short wheelbases are better on uneven tracks, where the mutual tilt of the axles has to keep all four wheels on the track.

It must be possible to work out a formula for the relatvity of wheelbase, wheel diameter and curve radius but that's for mathematicians, not for a practical minimal narrow gauge artist like me.
 
 
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