Slowing Down In The Curves

Yes, your toy trains, just like the real things, are a slave to the laws of physics, and it is inescapable that it requires more energy to pull a train through a curve than in a straight line.  And your guess is correct, the tighter the curve, the more pronounced the effect.  Your options are to use wider curves, run shorter trains, or invest in locomotives with (or upgrade the electronics in your existing motive power to)"cruise control."  Cruise control delivers only most of the track voltage to the motors, and when the built in sensor detects a slow down (due to curves or grades) it supplies the extra voltage to keep the speed constant.  (It also will reduce power on a downgrade to keep speed constant. )

It could be the size of your engine.  What engine are you using?

 

Rick

It could and it could not be.  I suggest the way to look at it is: all locomotives slow somewhat on curves (unless they are fitted with cruise control and it is turned on) and some are more sensitive (slow down more) on curves than others.  

 

It is more work for a loco pulling itself and/or a train around a curve.  Even though most locos and rolling stock have swiveling trucks that angle into the curve, there is a noticeable increase in friction on their wheels in a curve - and the tighter the curve, the greater that friction is.  Hence, the train slows.  But it varies with loco.  This is not just about power: generally a locomotive with a larger motor will be less sensitive, but it is largely about wheelbase.  A locomotive with a longer wheelbase will tend to slow more because that longer wheelbase creates more friction in a curve.  The wheelbase is the distance between the flanged drivers on a diesel's trucks or between the fartherest apart flanged drivers on a steamer's main driving wheels.   

 

To fix this, well one way is that youu could isolate the curves' track, and use resistors or such in the feed wires to the straight track and not to the curves, thus running higher voltage to the curves - this is a type of a "fix" for this.  If you do, my experience is that it takes about 2 volts extra on a O-36 curve, but of course that varies with the loco.  This is a lot of work - generally not worth it.

 

The other way is to buy locos with cruiser control.  Most will maintain constant speed, even if running conventionally (and if you follow the instructions) within reasons curves and slopes - the cruise will vary voltage to the motors by about 3 volts as needed..  My experience is that if more than 3 volts is needed they may trip out of cruise (you know it when they do).

 

And the third way is to just live with it.  Toy trains slow down in curves and up slopes.  Well, they do in the real world, too.

 

Several years ago, I did tests on my layout to determine the equivalence between curves and slopes: locos slow down on slopes, and they also slow down on curves. Thus they will slow down a lot on a sloped curve.  So I did tests to determine, say, what slope on an O-72 curve was equal to a 3% slope on straight track, etc.  This way I could layout my track so I would have no place that presented too much of a challenge to locos.  I used a RK Y6B and a Lionel 0-4-0 shifter and some others I forget now as my test locos.  I determined that O-72 with a 1% to 1.5% slope was equal to straight with 3% depending on loco, and I discovered that for some locos 0-36 was equal to a 3% slope even when level.  I laid out my entire layout thus: 0-72 curves limited to slopes of 1.25%, 60 to 1%, O-48 and O-36 as flat as I could get them.  

Two words: Cruise Control

If you were driving a real train, wouldn't you expect to slow down at curves, for safety reasons?  Your toys are performing prototypically, I think.

The friction that a train experiences when going thru a curve May be due to the fact that the outside wheels running on the outside rail are traveling a longer distance than the inside rail and since they are solidly connected by the same axle for each wheel set, friction exist between the wheels and the track and this slows down a non cruise controlled train. This friction does not happen on the straights since all wheels are traveling the same distance. Cars have slip differentials to reduce this loss of power when a car is turning (same as a loco going thru a curve). Some sports cars have limited slip diffs to increase traction to the road.....Just a thought!

Benjaman,

   It's not always bad that your trains slow down a little going into the curves, however 048 and 072 curves are definitely easier on the trains as they run.  It's not the size of the platform that matters, it's the feet of track you have out and how many power drops you have, that make the difference.  I recommend you do 2 things one get a bigger transformer, especially if you are running lighted rolling stock.  Run either DCS or Legacy/TMCC and get into cruise control, make sure you do your wiring correctly and have enough power to expand your layout when you so desire.

PCRR/Dave

 

I had the same problem with my previous layout, even with cruise control.  I found that one section of track was just too long for a single drop, so I added another one and everything ran fine.

Let us know what the problem was nd how you resolved it.

 

My two guesses are:  Add more "drop" power wires or real life physics!  

Most of my fleet is MTH PS2's and 3's with speed control and most of the time that's what I prefer for moving cars around with slow steady speed or slow running with sound. I also have some WBBs without speed control and really enjoy watching them gracefully speed up on straights and slow down on 036 curves. That's the beauty of NO speed control. Would be kind of boring otherwise. IMO.

The OP clearly stated that he already added additional power drops, so I'm confused as to why several responders keep advising him to do something he's already done without solving the problem.

gunrunnerjohn,

Can Cruise Control be added to ProtoSound 1 engines ?

 

I have a lionel 4-4-2 and I looked at some of the newer locos and some models have locomotive speed control is that the cruise control you talk about.

I'm a simple guy. Can "Cruise Control" be added to an Atlas GP 15 TMCC engine and can it be added to conventional engines.

 

Brent

It's physics. Any object that changes direction will expend energy doing so. Less energy=less speed. When you go around a corner in your car what happens? It slows down, even if you don't ease up on the accelerator. Trains are not different.  Only way to not slow down is to increase the energy. In a car that means pushing down on the gas pedal, on a train it means more electricity. Tighter the curve, the more energy you lose. I have O36 and O72 curves on my 5x10 layout and you don't notice the train slowing much through the O72 curves. 

 Agree.