RICHMOND, Va. (WRIC) — If you’ve taken a trip on an Amtrak train this summer, you may have noticed some delays and slower speeds than normal, something that is not by accident.

As temperatures remain high across the country, rail lines exposed to the constant heat can expand and pose a risk to trains that travel across them at high speeds. To keep riders and employees safe, Amtrak imposes heat restrictions which require conductors to slow down.

Amtrak monitors rail temperatures and weather conditions on the Northeast Corridor between Washington, D.C. and Boston, as well as the Michigan Line, Springfield Line in Connecticut and Massachusetts, Keystone Corridor in Pennsylvania and Empire Line in New York.

With a rail temperature of 131 degrees Fahrenheit, Amtrak imposes a maximum speed of 100 miles per hour and with a rail temperature of 140 degree Fahrenheit, Amtrak imposes a maximum speed of 80 miles per hour.

Also affected by changes in temperatures are catenary wires, overhead power lines which provide electrical power to trains on the Northeast and Keystone Corridors. As temperatures quickly rise and fall, the wires can expand or contract and the tension can increase or decrease dramatically, possibly causing components in the catenary system to fail.