Chris is correct. Union Pacific had applied lifters to about ten 4-6-6-4's when converted to oil in 1946. They also applied them to two of the coal burning engines, though the exact reasoning behind this has not been revealed given the loss of the internal "Mechanical Dept" correspondence. However, as Chris states, the 1953 trip was pulled by one of the two coal burners with lifters, 3967. So, when UP's Steam Crew committed to operating a 40th Anniversary special commemorating the first UP fan trip Steve Lee determined to fit up lifters made from the original drawings. You see those in your photo.
If I'm not mistaken, this first attempt did not include the spacers UP added when fitting the lifters in 1946, which moved the front of the lifters outward and helped eliminate the restricted view ahead from the cab. I know Steve Lee felt his vision was restricted badly. I believe this was corrected the next time Steve fitted the lifters, and I'd suppose it made a fairly decent difference in view ahead.
Regardless, thanks for the nice image!
John