A new rail link across the river will be built in all probability in Coquitlam in the United Boulevard area. Its also unlikely that it wont be a tunnel. A swing span bridge for the amount of train traffic (and increasing) doesnt make any sense in that part of the Fraser and a rail bridge in the New Westminster area makes even less sense. In Coquitlam and across the river in Surrey CP/CN both have the property and right of way available to make this work.
Ultimately if the new Fraser River port in Richmond gets the go ahead (and the region is smart) then a new rail link via a tunnel could be built from Delta to Richmond/Anacis island and a new, larger and consolidated rail yard can be built in Delta or even possibly Richmond. This would allow once and for all for the rail line and all the yards in New Westminster Burnaby and Vancouver to be decommissioned. It would allow New Westminster to be linked to the waterfront, remove all the train noise and problematic at grade rail crossings, remove the unprofitable spur line through the Fraser lands development and south Vancouver, and alloy for the rail yards in New Westminster to be redeveloped and the highrise community joined up with the rest of the city. If the region was a bit proactive then this could all be done for not much money , and on top of that the redevelopment of the rail yards/rights of way could bring in alot of money to CP to through back at the project. As a result the livability of the entire area stretching from Braid st to south vancouver would jump by leaps and bounds and the efficiency of the movement of goods both by rail and water would also jump.
Anyways I got a bit carried away but my main point was that a new rail crossing will almost certainly be in Coquitlam and as a tunnel. Everything else I said was just speculation/wild dream, though very realistic.
Couldent fall asleep so here are some quick pictures of what i mean.
red is the tunnel and runups to it.(remeber that a majority of the traffic comes from Coquitlam)
And for good messures here is all the other stuff I rambled on about. Red are tunnels and runups(except a new bridge to Anacis island), red square is new rail yard and blue square is the proposed port expansion). This would shave off 10's of km's of rail from the network, allow redevelopment of the rail yards and significantly improve efficiency. When(if) the port gets built then the existing residential communities and infrastructure would not be able to handle the increase in traffic anyways and expansion would be almost impossible so a new link from the south would be a must. A tunnel with the port would again be the best solution for that part of the river.
The new crossings would probably not cost much over a billion dollars, take away the proceeds from the land sales of the decommissioned rail/yards wich could be nearing half a billion in value, and then take in to account that both these links are/will be needed, and then the region/province could even fork out some money(probably not much if any at all) to make it happen since its in their best interest.
sorry if I went a bit off topic.