In the heat (of summer) the rails undergo thermal expansion. The amount of expansion is proportional to the normal length and, because rails are long lengths of metal, the expansion is sizeable. If there were no gaps then the expanding rails would push against one another until they buckled.
Railway lines are parallel
When the tracks expanded in hot weather, buckling of the rails would be the result.
No. Railway tracks are only the rails and ties/sleepers and hardware used to hold the track in place. A railway line is a set of tracks designed to move a train between at least 2 points. A railway line can consist of many tracks.
to allow for the thermal expansion or contraction
Iron is iron . . . but rails are made of high-strength steel. (Which is made from iron.)
You would need rails, detector rails, power rails, and minecarts.
the rails and engines accourding to Julilly from underground to canada by barbara smucker is the underground railroad or railway.
The gap is there to prevent the rails expanding and buckling during very hot weather.
The thermit reaction is used on railway lines to join or weld together pieces of steel rails. It creates a strong and durable bond between the rails, which helps to maintain the structural integrity of the track and prevent rail breaks or gaps. Additionally, thermit welding is a fast and efficient method that can be done on-site without the need for specialized equipment.
For heat expansion.
An example of parallel lines are the two rails of a railway track, rails which never meet. An oval is a line or shape that has no parallel lines.
The two rails on a railway track is an example of two parallel lines. Nowhere will they move towards or away from each other, or a train would not be able to travel along them.