Prince of Wales maintenance

Picture taken yesterday from the bike path on the west side of the War Museum, looking upriver. A service vehicle is on the Prince of Wales bridge near the Quebec side.
Closer view, shows the vehicle has two sets of wheels, rubber ones for the road and steel wheels for driving on rails. What it is doing?
Men in cherry picker extendable arm are working on the side of the bridge.
Arm continues to extend, now right under the whole bridge, the men are beyond the far side of their vehicle. It is rather like using your left hand to scratch your right side.
Working on the underside. Double click to enlarge.
Recently while cycling past the Quebec side of the POW bridge I noticed a security guard on duty, guarding the track/bridge. Upon questioning, I found out there is a guard on duty 24/7. He prevents people from cutting across the river via the bridge (the big fences at each end having been kicked down by thwarted peds). Upon further questioning, he said he was guarding the Fibre Optic Cable (FoC — as seen frequently painted on downtown streets, along with Bell and other cables that get marked). What is there to steal in FoC? I thought FoC was plastic tube, not copper wire.