Question

Before you get ready to go diving, you really want to eat a snow cone. You know there is a small food stand on the other side of the railroad tracks near the beach. As you carefully step over the tracks (making sure to look both ways first!), you notice interlocking joints between some of the tracks. What are these joints called? What purpose do they serve? Describe thermal expansion and why these joints are necessary.

Answer 1

Breather switches

Step-by-step explanation:

1) Name:

These interlocking joints between rails roads are called Breather Switches. They are also known as Adjustment Switches and Expansion Gaps

2) Purpose:

They protect the trains from derailment by allowing the rail road to expand

3) Thermal expansion & necessity of these joints:

When heated every object will undergo a change in size or shape. This phenomenon is called thermal expansion. There are three type of thermal expansion.

1. Linear expansion - Length of the object increases when the temperature is increased
2. Volume expansion - Volume of the object increases when the temperature is increased
3. Area expansion - Area of the object increases when the temperature increased

The rail roads are heated every time a train passes over them, due to the effect of friction. The rail roads are also heated by the sun during the day especially in the summer. Since the railroads are one dimensional objects (their length are comparatively larger than their breath and height), there will be a significant linear expansion. If there were no gaps left between them they will bend the track out of shape. This will cause derailment of trains.

So it is necessary to leave gap between the rail roads to prevent derailment.

Answer 2

These interlocking joints are known as breather switches which are also known as expansion joints or adjustment switch. This is an intentional gap provided to allow for expansion of the rail, which may expand at different rates. These switches reduce the gap between the rails and also act as relief points for the track.