I have what is probably a track problem that I don't know how to solve.
Most of my steam locomotives run fast of the straightaways and slow
significantly on the curves. Track voltage is consistant all the way around
so I'm thinking that there is some binding on the curves. I don't have room
to make the curves any wider so does anyone have any suggestions?
Well Carter, What you are seeing is "Physics in action".
It takes more power (effort) for the train to traverse curves than it
does straight track. The sharper the curve, the more noticeable the effect.
So, no, there isn't anything wrong (easily fixable), More power (voltage
available on the track) will bring the speed back up, but YOU have to be
at the controls turning up the power (And slowing things back down once
the curve is past).
I think that the NMRA standards for HO gauge is around 0.640 minimum to
about 0.670 maximum, with a wider gauge recommended on curves. I made a
brass gauge gauge :-) that mikes out to something like 0.643 on one end and
0.672 on the other. I had a section that was too narrow, possibly from a
habit of laying my automotive drop light on the rails for a couple of
minutes when doing something tiny on the layout that needs two hands. I
think I softened the plastic ties and it narrowed the gauge. You could
actually look head on at the oncoming loco and see it ride up on one side
for a second or two.
Anyway, I later deliberately appied the drop light heat for a couple of
minutes, then angled the gauge in and twisted it perpendicular to the rail
and let everything cool for an hour. Presto!! It was fixed.
BTW, I once melted / deformed about 10 ties in a row leaving the light lay
there too long, and had to remove and replace that section of ties. It was
kind of fun drilling the little holes and applying the spikes on the new
You could try my method, or replace one rail on the curve, making the gauge
a little looser. Is this a steam engine you are having this problem with?
Are the middle drivers blind?
If you don't want (or have the machining skills) to make a track gauge of
your own, your local hobby shop should carry NMRA standards gauges.
They're about $12 in my area now, but they're an essential purchase.
They do more than just track, too.
Wise is the man who attempts to answer his question before asking it.
To email me directly, send a message to puckdropper (at) fastmail.fm
Dear Mark, David and Steve.........my apologies for the confusion. I didn't
realize that you all attended government school. These things are supposed
to be intuitive for males.
Anyway, my rememberances about the HO gauges are in inches, but they were
The Official NMRA Standard 3.2 numbers are.........drum roll.........
0.649 inches for straight track (tangents)
0.672 inches maximum, with thoughts about widening the gauge on curves
discussed in NMRA Recommended Practices 8
For my railroad pals living in other countries, like Hoboken and Utah, that
works out to be
16.4757 millimeters for tangents
17.059 millimeters max
81.9 Microfurlongs for tangents
84.8 Microfurlongs max
Some figures rounded, some figures truncated, all figures subject to change
BTW Carter, Charles was correct too. Railroad wheels have no differential,
so on curves one wheel or the other on each axel is going to be sliding on
the rail a little. Plus there is a lot of scrapping of the outer wheel
flange on the inside of the rail head too, all combining to add drag and
produce those lovely echoing "chalk on a blackboard" "my teeth are cracking"
harmonies heard while traversing tight curves on the subway.
There is a differential effect through the wheel treads being coned.
The wheel diameter beside the flange is larger than the wheel diameter
at the outer edge.
On straight track the wheels/axle should centre itself on the rails so
causing the wheels to sit on points of the same diameter and on curves
the wheelsets move across so that the outer wheel will ride near the
flange while the inner wheel will ride near the tread outer edge.
There probably isn't enough coning to accomodate 15" curves.
That noise comes from the flanges touching the rail at an angle.
(although I believe that some US suburban lines don't have coned
Well I never thought of that Greg. Brilliant those 19th century RR
mechanical engineers, and you're pretty sharp too !
So on really tight curves the flanges can rub against the inside of the
outside railhead in front of and/or behind the axle center line ?
Between you and Professor GP, I'll be and expert too if I live long enough
The Professor turned me on to the Yahoo EarlyRail group. I didn't know
there was such a group 2 months ago. The era interests me most, but I
actually like all aspects of the hobby.
BTW, we've had a day here and there in the 70s. Is there an ocassional
chill in the air where you are?
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