The space between the 2nd and 3rd drive wheels is very common on many locomotives with 2-3-0 arrangement, to have a better weight distribution, without using a rear axis as the Pacific locomotives do (2-3-1)

Another one for ita locs. +1 steamer

Funny, I never noticed that strange gap between the back and middle driving wheels before, but that really seems to have been a thing with the P8.