has seen working

[Maybo]

The Hertford Union Canal was never a commercial success, but it runs alongside the busy Victoria Park and has seen working, wartime and leisure activity for close to 200 years, as well as industry along its banks.
(Hidden treasure: Hertford Union Canal gives up its secrets by BBC)

Is it "The Hertford Union Canal has seen working"? What does it mean?
Can I replace the comma before wartime with during?

 

[emsr2d2]

"Working", "wartime" and "leisure" are all connected to "activity". The canal has seen three different types of activity.

 

[Charlie Bernstein]

So no.

 

[GoesStation]

It doesn't say has seen working. It says the canal has seen working activity.