Many substances were utilized for air and water hoses—none ever worked truly well. Being constantly exposed to the environment, they regularly cracked, sprang leaks, froze in the winter, and deteriorated in the hot sun. They could be punctured, twisted and crimped, and torn off during switching movements, and they required constant replacement. Many trains were unexpectedly halted far from a station when a hose burst (and when it was an air hose on a train moving downgrade, an accident sometimes followed).