Mallet locomotive
Steam powered tank locomotives were always given an "E", and the maximum speed of the locomotive was designated with a lower case letter. Thus, an Ea 3/6 was a tank locomotive with vmax &gt; , three coupled drive axles, and three unpowered axles. With steam locomotives, separate driving mechanisms were displayed. So, for example, a Mallet locomotive was named G 2x2/2 or G 2/3+2/2, and not G 4/4 or G 4/5.