as temperature during the day increases , the temperature in an environment will increase & as the temperature of an environment increase, the objects in the environment will increase in temperature ->  as the temperautre of the day increases, the objects in the environment will increase in temperature  as the temperautre of the day increases, the objects in the environment will increase in temperature & as the temperature of an object increases , the size of that object will increase ->  as the temperature of the day increases, the size of the objects in the environment will increase  as the temperature of the day increases, the size of the objects in the environment will increase & the metal railroad tracks are out during the day & temperature increases during the day ->  the size of the metal railroad tracks will increase during the day  the size of the metal railroad tracks will increase during the day & length is a part of size -> the length of the metal railroad tracks will also increase during the day