How is it that some rail lines do not have any expansion breaks?

Question

I mean: the breaks between rail lines that cause trains to make a sound as they move across them. This break is to allow for rail expansion. Some rail lines do not have them. How do they get away with it?

Answer 1

All rail lines have them.  They HAVE to have them.  In the heat of the summer they may be closer together and you might not be able to hear it.

Answer 2

Years ago welding technology wasn't what it is today.So rails were bolted together.It made for a rough ride and every time you hear that little click the wheels made going over that joint it was a bit of wear on the rail.Now ribbon rail is used by most railroads because it lasts much longer and with less maintenance.Expansion joints do have advantages but not enough to use them.Ribbon rail is prone to breaks in very cold weather caused by the rail shrinking.It can also develop what we call a sun kink from very hot weather.But most of the time it is fine.Modern ribbon rail is held in place using rail anchors which are clipped onto the rail on each side of the ties as well as the spikes.The anchors keep the rail from shifting in weather extremes.

Answer 3

Andy and Rango have already wrapped this one up. But I will add to this, that some older branch lines on our railroad are still 39 foot rail sections. And if a rail is going to break, 90 percent of the time it's at the joint. That's where the wheels pound the more vulnerable end of the rail. And the advantage of ribbon rail really surfaces.

Answer 4

Welded rail is rail that has no breaks in it, at all, for miles.  It is spiked down very securely so that it only expands in width and height, not length (although that does happen sometimes - see the other answers for explanations of heat kinks).  However, there are places in the rail where there are breaks - they occur where the railway's signalling system intervals are.  The railroad signals operate by sending an electric current through the rails and using that current to test for the presence of a train (or a break in the rails).  Every mile or two, there is a new signal post, so there has to be an electrical separation between signal posts, so that the signal system only sees things in its own little block.  The separation is usually a little 1/8" insulator supported by bolted, insulated joint bars.  These are not heat expansion joints - rail is designed to stay the same length, regardless of heat, by being securely fastened down.  When the fasteners fail in conditions of extreme heat, or the rail breaks in extreme cold and stress, the result can be really bad (but entertaining if you weren't there at the time).

Answer 5

If the rail is anchored very very tightly the expansion can be contained so that the rail is held in place and expands vertically.

This means the rail has to be spiked tightly to the ties and they are also fitted with special anchors that stop the rail from moving in a lenghtwise direction, the ties also have to have more ballast or gravel packed around them to hold the rail in place.

As you can imagine the tension to kick out sideways is tremendous on a hot day, known as thermal buckling or "sun kinks". They do happen although not as often as one might expect. Rail temperatures on hot afternoons can often go well above 130 degrees.

Most modern rail is CWR or cointinuous welded rail. Rail joints on bolted rail is expensive to maintain and the worst wear place on rail so the extra effort is well worth the money for railroads.

Good question, very observant.

Answer 6

Those breaks are NOT for expansion.  It's because the steel mill can only roll the rail so long out of a single ingot of steel.  

Rail was bolted because welding wasn't possible before the 1950s.   Joints do not provide for expansion (they wouldn't be enough).  In the cold the rail tries to stretch, but cannot, so it stretches like a guitar string.  This force can actually bend the bolts inside the joint.  No kidding!  Many joints are rusted solid and can't move.  I can show you plenty of those too.

Rail sections are actually shorter than the steel mill can roll.  The problem is delivery.  In the old days, they delivered rail in 34 foot gondola cars -- thus 33 foot rail.  Then the standard became 40 foot gondolas - 39 foot rail.  Modern railcars are much longer, so a standard rail stick is 78 feet (39 x 2 for easy replacement).

Oh and unusually, Skidderback is wrong.  You don't want expansion joints because the rail would "walk" to and from them every day.  This would cause a ratcheting action which would push ties out of position and make a maintenance nightmare.  You want rail staying put, which is why you see rail anchors on ties.  The only place they ever use expansion joints is to isolate bridges or other special trackwork that would be damaged by endwise force from the rail.   (for instance a drawbridge on a hot day, you can't have the rail trying to expand pushing on the drawbridge and pinching it so it won't open.)