It's hard to be totally certain by the pictures, but what it looks like is:
1st armature looks like Dorfan, looks like the brushplates at the bottom the Steve identified are probably for that. 2nd armature, small one with small pinion gear is likely a OM-16. Late prewar and early postwar it was used in 0-4-0 1662, 1663, 1665 and 1656 switchers. Also small 2-4-2's 1684, 1664, 1654 and 1655 locos. 3rd armature, large with a small pinion is either a 1668 or 2026M, used in medium sized steam, 1668, 1666, 2026. Last one with a large pinion is a 262-23. Used in prewar 261, 262, and 249 2-4-2's.