It's an interesting set. All of the track, straight, curved, switches, and bridge have little metal tabs with numbers riveted to them. The numbers correspond to the numbers assigned to the track in the diagram that came with the set. The street lamps have a very different glass globe which provides a great visual impression when you turn them on and turn off all of the lights in the room.
As you will see when you check the websites mentioned above there were "early" and "late" versions of the signals and the bridge as well as the locomotive casting and color.