Stalling. Snaking upgrade through Tunnels 1 and 2 at just 3 mph, UP 5260 south and two fellow GE's are close to loosing the battle of getting the ILTSIR-31 over Tehachapi this morning. While a relatively normal length and weight, the second motor on today's train, UP 2642, has developed a mechanical issue that is preventing it from providing maximum horsepower. As such, the first and third units are doing all they can to pick up the slack but at slowly failing as the train would eventually bog down to a crawl as it limped onto the Allard Horseshoe curve. Taking in this show of mountain railroading is the crew onboard the UP 8095 north that is patiently waiting in the siding at North Bealville for the passage of the southbound intermodal. UP 5620's train would eventually pick up some speed at Bealville but would ultimately stall out shortly after the head-end exited Tunnel 5 and entered Cliff. Of particularly interest, Tunnels 1 and 2 on Tehachapi were bored through soft rock but still required some of the 600 kegs of Hercules Powder that the Southern Pacific used every week during the construction of the railroad between 1875-1876.