Vehicles help set the era on a layout.

This layout has 3 different eras that are changed every few months.  Besides swapping out the locomotives and freight cars to match the era, I also swap out some of the vehicles on the layout.

In this example I am changing from the 89-96 era to the 75-82 era.  The most notable changes are made in fleet type vehicles.  The fire station in Carlin has 3 doors that can be opened or closed so I don't actually change the fire apparatus but just open different doors.  The door on the left is opened in the 1988 to 1996 era showing an International 1990's era fire engine from a Lineside Models cast resin kit.

In the 2 earlier eras modeled on this layout, that door is closed and the other two are opened exposing an Ford C cab pumper by Athearn and a 1963 Chevrolet fire engine from a Lineside Models cast resin kit.  

Maintenance of Way vehicles are going to be noticeably different in different eras.  In this case I have swapped out my Union Pacific trucks with Western Pacific ones.  The large UP truck was built from a Showcase Miniatures kit, the van is from a Lineside Models cast resin kit, and a Ford F-150 pickup from Atlas.

The Western Pacific vehicles include a cast resin Chevrolet flatbed truck kit from Lineside Models and a Ford F-100 pickup from Atlas. 

The U-Haul dealer which is part of the Sinclair gas station is another example of where vehicles can be swapped out to suggest a different time period.  The type and paint schemes on these rental trailers had dramatically changed during the 1980's.