Metrolink’s 57 mile Los Angeles-San Bernardino (CA) mainline is basically single-track.
However, at CP KAISER, it looks like a four-track main. View looks west from the Cherry Ave. overpass

Early on a Sunday morning, one signal goes green …

… and then a Metrolink in push mode comes speeding by on its way to Los Angeles. The yard on the left is BNSF Railway’s Kaiser Yard.

A BNSF comes out of the yard and crosses over the mainline

At the east end of the BNSF Kaiser Yard, a “warbonnet” awaits duty. The Cherry Ave. overpass in the background is two miles away

From Beech Ave., view looks east toward CP BEECH where the line becomes single-track again …In the foreground, a bird lands on (or a squirrel climbs onto) a railhead, and is totally oblivious to the fact that Santa Fe passenger trains with such great names as Chief, Super Chief, and El Capitan plied this very ro
Los Angeles once really did have a four-track commuter main. Pacific Electric’s Long Beach line north of Watts was a four-track main with the outer tracks for Watts locals and the inner tracks for Long-Beach expresses.
Does the “CP” in “CP KAISER” mean something other than Canadian Pacific? [wow][D)] - a.s.
CP stands for Control Point, which is often used in DTC control and on dispatcher’s displays.
Another bit of knowledge to lessen my ignorance. Thanks! - al
CSSHEGEWISCH:
Oh, I remember that four-track Pacific Electric line from Watts to Los Angeles! As a kid in the early 1960’s, my residence was on the east end of the PE system. One day my parents visited the Firestone area, and I saw SP 4613 (a small switch engine) northbound on that four-track main. It had been a periodic visitor to the eastern end, so it was like seeing an old friend. Who could have imagined back then rail transit would disappear for years, and return again in the form of Metrolink, and use former PE tracks AND the ex-Santa Fe tracks that passed Kaiser to get to the east end.