Don't we have that?
Maybe its because people like sp? I dont know. I mean, we do have a lot of steam fans out there and SP engines present themselves as a unique challenge.
I thought up some reasons why:
SPecialization: From the start, SP had to deal with many forms of land and environs, from the cold and rocky donner pass, the southern deserts and the expansive farming valleys. This lead to SP having to preform various engineering feats, both for the routes they made and the engines that ran them, the cab fores and the SD45T-2s (SD45-2s modified so they would not overheat when heading through the tunnels and snowsheds on SPs system) being prime examples. SP also helped develop many technologies such as refrigerator cars (specifically its joint UP PFE fleet) to help get CAs produce to market.
SP had many interesting locomotives, not only their cab fores but also things like the K-M 4000 diesels
Paint: I have heard SPs daylight scheme be called the most beautiful railroad scheme in the US, something i do agree with. (despite me liking all US railroad paint schemes, and my belief that the best SP scheme was black widow)
Routes: SP had some of the most beautiful routes, from Donner pass to the techapi loop, and they had their beautiful daylight passenger trains to run through them.
Affects on the lands around their lines: SP left a major mark on the people and towns of CA, from helping link the state to the rest of the US, attracting new people to come to the state, and helping to turn the state into a major farming and economical powerhouse by helping move the states produce to country, and world wide markets.
One statistic that shows how big SP was in CA is the fact that at one point half the population of Sacramento, the capitol of the state, worked to some extent at the sac shops.
SP also heavily affected those who lived by their lines, and many old Californians can attest to seeing a SP train at one point in their lives, and i would not be surprised if the company inspired many to become railfans and hobbyists. I was certainly inspired (Well it was UP by the time i was born, but you get the idea)
So...yeah.....those are my ideas........kinda got abit long at the end there but...i think it got the point across.
(P.S did anyone see what i did with the word "specialization"? Anyone?)