Just west of the Union Pacific's Salt Lake City depot was a junction of UP's Provo to Ogden line (former Oregon Short Line trackage) and Los Angeles & Salt Lake line, with the Denver & Rio Grande Western's Salt Lake to Ogden line cutting across the UP's tracks. Interestingly, the interlocking tower handling this tangle (Grant Tower) was operated by the D&RGW. This view inside the tower provides a pretty clear picture of the whole, with east being up on the CTC board.
For a wealth of information about this tower see utahrails.net/utahrails/grant-tower.php.
