These two videos were posted on March 17 of this year:
▶ Gold Line flyover - YouTube
▶ East Rail Line flyover - YouTube
Both by helicopter, and in some parts, you can see the helicopter's shadow. Both flyovers start at Denver Union Station and end at the ends of their respective lines.
The Gold Line:
At 23rd St., it has a double-track flyover bridge just to the south of it, a bridge that touches down a bit before Fox St. to the east of the tracks and the yard. It has another double-track flyover turning west before Pecos St. A cleared double-track right-of-way follows I-76, and there is a double-track viaduct a bit past I-76 on the north side of the tracks. Construction of it peters out just before the lakes at Lowell Blvd., however. The helicopter chose the southern track at the junction just after Sheridan Blvd., the single-track line.
Between that track and Grandview Ave. to the north, there is more than enough room for a double-track line. There's a double-track bridge over Wadsworth Bypass, and a new grade crossing at another street, but not much other evidence of construction. A bit east of Kipling St. there is some cleared area wide enough for double tracks, and a long stretch of cleared area west of that street, though no new RR bridge over it. There's a track in parts of that cleared area -- a single track.
The East Line:
A cleared right of way starts at Coors Field, just south of where 23rd St. splits into 22nd St. and Park Ave. A pair of tracks starts a little south of Broadway then goes in a bridge over that street. The tracks have two crossover switches in place, and it ends a bit before a bridge over 38th St. The cleared right-of-way turns east along E 40th Ave. between that street and the existing tracks, stopping at York St. The helicopter then went northeast to some eastbound tracks and then followed them. Very little evidence of construction except for a double grade crossing at Holly St. and some cleared right-of-way in each direction from it. East of Holly St. there are what look like stacks of concrete ties. Quebec St. has a double-track bridge and cleared right-of-way on each side. Just east of Central Park Blvd. is a double-track bridge over Sand Creek. Then some tracks start, with poles on each side, though the south-side one stops then restarts. A double-track grade crossing at Havana St. with some white area east of it. A station? Cleared right-of-way with poles and no tracks east of Peoria St. Sable Blvd. has a double-track grade crossing, though N Chambers Rd. doesn't.
Just before N Airport Blvd. is a single-track northward flyover. It becomes double-track soon after that street, though I'm inferring how many tracks from its width. The right-of-way stays double-track for a long stretch with tracks present in most of it until not long before it curves to follow Pena Blvd's curve. It becomes single track with poles on only one side and stays that way for another long stretch, though its right of way is wide enough for two tracks, and it has double-track bridges over Tower Rd. and SR-470. It then turns northeast, becomes double again, crosses Pena Blvd., then turns east. It goes between 78th Ave. and 79th Ave., with some of the airport's runways visible on the left. Two crossovers, then the tracks stop. Then a double-track flyover over part of Pena Blvd. It stops before the "X box", a crossover underneath two branches of Pena Blvd., though the right-of-way is cleared. It continues to the airport terminal building, where there looks like a station platform with a slab foundation for a track on each side.
