At the start of 1956, the last full year of SP std. gauge steam, the railroad still had 12 different wheel arrangements. I am not counting shop switchers.
One of those was the Mogul. One of the reasons for this is that they could be trusted to make meets on the mainline
with those big 63" drivers. They showed up on train orders regularly between Redding, CA and Bakersfield.
I knew a Western Division engineman in the early 70's who told me that they ran them on freights at 50 all the time.
There could be a particular mechanical reason that 1744 did so poorly at speed while on the SLRG.
The other active wheel arrangements in early 1956?
0-6-0
4-6-0
4-6-2
0-8-0
2-8-0
2-8-2
4-8-2
4-8-4
2-10-2
4-8-8-2
2-8-8-4 (3804 and 3805 on the Modoc until around late March)