I find that hard to believe because UP doesn't have any "DS"s. They have Dispatchers. Clarification here, the initials "DS" is only used on BNSF Railway. Reason is in the olden days of the Telegraph Key, when you transmitted "DS" that was the code meaning Dispatcher. UP and the other R.R.'s it absorbed, never refered to their Dispatchers as "DS". I made the mistake myself about 18 years ago, calling a UP Dispatcher a "DS" by mistake, and boy, did I get to hear about it! Never made that mistake again, thats for sure. I cannot say on here what they feel DS really means, because it is foul language, but ask me in person sometime.