This is a picture of a UP freight making its way west out of Denver, along the Moffat Tunnel line.  If I remember correctly, there were seven engines on the front end of this train.

Same train as to the left.  The tracks continue up the hill side, and can be seen just above and left of the engine's cab, and to the right of the tree.

Here's a UP coal train heading east, towards Denver after having made its way through the mountains.

Every summer, the UP runs a special steam powered excursion from Denver to Cheyenne to bring people to the Frontier Days celebration.  In 2000, the Challenger was used for the excursion.  This picture was taken in the early evening, as the train was making its way back to Denver.

The Sun had just dropped below some clouds, and was just above the mountains, producing a typical beautiful Colorado Sun set.  It also helped to produce some interesting color variations between the ground, sky, and passenger cars.

The weekend after the Frontier Days excursion, the Challenger left Cheyenne for Los Angeles.  Here's the train leaving the UP yard at Cheyenne, passing below the old Colorado & Southern mainline, now used by BNSF.

The train was short, only about 6 or 7 cars long, and no diesel backup engine.  The rest of the UP excursion fleet was out East for the Republican National Convention, and the Challenger was heading to the Democratic National Convention.

Here's the train pulling into the Laramie yard to get greased and oiled before continuing west.

West of Laramie, I got this nice sequence of pictures.