In the obligatory 4449 category, chasing the "Disney Daylight" from Pinole to San Luis Obispo (1986, I think). In 1980, the UP inspection train on the WP pulled by A-B-B-A E-units--chased it all the way from Oakland to Reno Junction. Really remarkable: a two-day trip to the Modoc Line in 1990--arrived in Wendel just as a westbound was departing and chased it until the light gave out about the Oregon line. Next day, chased the BN Bieber turn (pulled by leased McCloud SD38s!) to Stronghold, waited half an hour for an SP Modoc eastbound (with five D&RGW units on the point), and chased it almost to Wendel before it got dark. Lordy, I've had some good luck over the years.