BSTL 895, 4962, and illegible number

Three containers owned by an unknown reporting mark. It appears on lists as just "BSTL". One other picture of a container with BSTL reporting mark found on the internet. Perhaps a clue here is they seem associated with signals for the BNSF.

BNSF Longmont yard, Longmont, Colorado

Leica IIc, Leitz Elmar f3.5/50mm, Kodak Ektar 100