8/20/92: Espee trackage rights on the Racetrack at LaVergne. SP SD40R built in 5/68 (note the trad. SP light package! Nice!!) leads a DRGW SD45 (5330 built 4/68, rebuilt 4/95 to CPRail SD40M-2 5496), a tunnel motor and a BN SD40-2 on a freight.
It was really cool to see these at night! Once on the BN (before it was BNSF) an SP run-through came at night and I couldn't figure out why one headlight was blinking above the other! Then I saw the Gyro-light and it was so cool...better than boring ditch-lights!
I wish I could have seen an SP unit like that at night. I have seen some units at night that have the Gyro lights, and those look a lot cooler than bland ditch lights! The first time I saw an unit with a gyro light, I thought I was seeing things until the unit got close to me.
I'm sending you a link to Wikipedia that shows Tunnel Motors, click on the picture and you can see the profile and how the radiator intakes at the rear are different from a regular SD40/45 [link] This article I think explains it really well.