The 40-ft-long A-36 steel rails on a train track are laid with a small gap between them to allow for thermal expansion. Determin
e the required gap d so that the rails just touch one another when the temperature is increased from T1=-20F to T2=90F. Using this gap, what would be the axial force in the rails if the temperature rises to T3=110F? The cross-sectional area of each rail is 5.10 in2
