A history of the G N R shows an engraving of the engine sheds in 1851,there are several horses in the scene, also a reference to a petition by the men for houses to be provided because of the appalling shortage of accomodation in the area, repeated again in 1853, and ignored again by management.
It would not be unusual for them to be living in makeshift accomodation on railway-owned land, but i still cant think what the initials mean, but agars town would fit the bill, but its always descibed as a shanty town, and not the place anyone in employment would contemplate.
Mazi's oh