Railway Paymaster's Building

Unknown: What is the story behind this building, all I know is it was the railroad's paymaster building.  It is near Plant Bath Pool on the opposite side of the road and bridge near City Centre (another story). I had a brief look inside one day, where I saw a lot of wooden office moulding and interior windows, along with the paymaster's safe (walk in size) that exists in the building to this day.  It is odd the way it stands out as a lone bump in the parking lot of City Centre, most of the rest of the Lebreton Flats having been demolished.