When, in 1866, Austria saw that she could not hold back the Prussian invader, she took off into Hungary no fewer than 1,000 locomotives and 16,000 wagons from the railways in Bohemia and Saxony. Similar tactics were adopted by the Boers as against ourselves in the war in South Africa. On the British troops crossing into the Orange Free State, from Cape Colony, they found that the retreating enemy had withdrawn all their rolling stock, as well as all their staffs from the railway stations, leaving behind only a more or less damaged line of railway. Subsequently, when the forces occupied Pretoria, they certainly did find there sixteen locomotives and 400 trucks; but the station books showed that in the previous forty-eight hours no fewer than seventy trains, many of them drawn by two engines, had been sent east in the direction of Delagoa Bay. When it is not practicable to withdraw locomotives and rolling stock which it is desired the enemy shall not be able to use, the obvious alternative is that measures should be taken either to remove vital parts or to ensure their destruction. Certain of the methods adopted during the Civil War in America were especially efficacious in attaining the latter result. In some instances trains were started running and then--driver and fireman leaping off the engine--were left to go into a river, or to fall through a broken viaduct. In other instances two trains, after having had a good supply of explosives put in them, would be allowed to dash into one another at full speed. Many locomotives had their boilers burst, and wagons were set on fire after having been filled up with combustibles. Still another method which has been adopted with a view to preventing an enemy from using the railways he might succeed in capturing is that of constructing them with a _different gauge_. The standard gauge of the main-line railways in France, Germany, Holland, Belgium, Denmark, Austria-Hungary, Italy, Switzerland, Roumania and Turkey (like that, also, of railways in Great Britain, Canada and the United States), is 4ft. 8½in., allowing trains to pass readily from one country to the other with the same rolling stock; but the gauge of the Russian railways is 5ft., necessitating a transshipment from one train to another when the frontier is reached. Similar conditions are found in Spain and Portugal, where the standard gauge is 5ft. 6in.[11]