Why are there no expansion joints on high-speed rail tracks, and how is the problem of thermal expansion and contraction solved?

In the past, a rail was 12.5 meters long, and when passing through the rail seam, thewheels would hit the end face of the track, and there would be a clicking sound. At thistime, the wooden pillow is actually placed on the gravel, calledThere is a ballast track. The stone at this time plays a role in delaying the impact. The length of the track is only12.5 meters, and there is a gap at the end of the track, and its ductility is negligible. At thistime, the speed was not fast, tens or hundreds of kilometers, and the wheels at this timecould still withstand the impact.

There are wooden piliows under the tracks, as well as concrete pillows

The joints of the tracks are approximately two centimeters

Stones can be found everywhere, just break them. Because it is paved with gravel, when itrains heavily, the water flows directly down the gaps in the stones. Because it is a stone,there will be no small animals that want to come in to make a nest, at most it will rain andgrow a little weeds, so it is inGeneral speed railway+ The ballast track is the most used.

But after changing to high-speed rail.... At 350 kilometers per hour, this time it was a bigproblem. Under such a high speed impact, the end face of the track will definitely cause animpact on the wheels, and it may overturn.

So the track was made longer and longer, and the length of a track was 400 meters. Forsuch a long distance, the ductility of the track cannot be ignored. I have seen the ductilityof steel with my own eyes. I did a project with a 60-meter railing with no joints in themiddle. By the summer of the following year, the stainless steel glass railing extendeddirectly to the front by about a centimeter and a half, and even the glass was squeezedout. In winter, the stainless steel railing on the other side was broken at the weld.

Since steel is malleable, which is its physical property, what can we do?

The solution is simple and crude.

Steel has stretchability, right, watch me work miracles!

The temperature of each region in recent decades is recorded, and the degree oftemperature change during this period is calculated, and then it goes upHydraulic presses* If you pull this rail to the center to this extent, and then buckle it to death every 1 meterand every 1 meter, won't the high-speed rail track be able to break free?

So there is a 6-meter-long concrete block under the track, 20 centimeters thick,prefabricated in the field, with super high strength.

This piece of concrete weighs almost ten tons.

Do you think that's the end?

No, there is more below Concrete baset......

The track was firmly locked to the concrete.....No matter how awesome the elasticity is, itis not worth mentioning in front of concrete.

Heat expansion and cold contraction.