At first American locomotives were shipped in knocked-down parts and set up again after their arrival in France. But this method consumed too much time, when time cost high in human life and treasure. A hurried search was made for ships with holds and hatches big enough to receive such burdens. The first ship that went thus loaded carried thirty-three standard locomotives and tenders tightly packed in bales of hay. Each one was lifted from the rails beside the dock by a huge derrick, as easily as a cat lifts a kitten, and on the other side was lifted from its place in the hold to the rails, ready for express service to the front, in forty-six minutes. In all, 1,500 locomotives, either knocked-down or ready for service, were transported and 20,000 freight cars were taken over in knocked-down parts and erected again at a big assembling station. There were constructed 850 miles of standard gauge railroads for needs which the existing French railways did not meet, of which 500 miles were built in the last five months of the war. In addition, there were constructed 115 miles of light railway, while 140 miles of German light railway were repaired and made fit for operation. In order to carry our own lines across French roads without interfering with traffic it was necessary to build many miles of switches and cut-offs. Americans operated 225 miles of French railways. The transportation system made use also of 400 miles of inland waterways on which hundreds of barges towed by tugs sent over for that purpose carried army supplies. This entire huge transportation system was planned, developed, operated and manned by American railroad men, from railway company presidents and general managers to brakemen, and required the services of more than 70,000 men. The aviation program called for big construction works in France, where seventeen large flying fields, divided into several air instruction centers, were developed. One of these aviation centers covered thirty-six square miles and was a city complete in itself, as was each of the other centers, with their barracks, dining halls, hangars, repair and assembly shops, hospital, officers’ and nurses’ quarters, welfare buildings. And all of these complete, self-contained cities, each housing thousands of people, grew in less than a year upon farming lands.