MELGAR posted:These photographs show my MTH Premier ATSF 2-10-4 Texas-type #5012 steam locomotive on Atlas O-54 curved track. I used a plastic triangle set against the side of the engine and a steel rule to measure the overhangs.
The 2-10-4 Texas-type cab overhang is 1-23/32 inches measured from the (outer edge of the) outside rail compared to 1-13/16 inches for the 4-8-4 Northern. Thus, the cab overhang of the 2-10-4 is 3/32 inches less than on the 4-8-4.
The 2-10-4 overhang at the pilot truck is 1-3/16 inches compared to 1-3/8 inches for the 4-8-4. Thus, the pilot overhang of the 2-10-4 is 3/16 inches less than on the 4-8-4
On the 2-10-4, the third driver is completely off the inner edge of the outer rail on the O-54 curve. This is consistent with the longer rigid wheelbase of the 2-10-4 compared to the 4-8-4.
It appears that the front and rear trucks have adequate range of motion for both models to operate on Atlas O-54 curved track.
Thus, based on cab and pilot overhang, it appears that the 2-10-4 has better turning performance than the 4-8-4 on Atlas O-54 curved track.
MELGAR
Thank you for the measurements. I'm quite surprised that the 2-10-4 actually has less overhang than the 4-8-4. Although the 2-10-4 has the wheels hanging off the inside of the curve on 054 it actually works. I'm quite surprised by that, and it gives me more options as far as equipment goes.
I measured my MTH Premier Southern Pacific GS4 Northern this morning on the Lionel 054 curves on my layout. I measured from the top of the rail head like you did. It has virtually identical measurements to the Santa Fe 2900 class Northern you have. Front overhang is 1-7/16", rear overhang is 1-13/16". When going around the 054 curve closest to a 072 curve on my layout there is 1/4" clearance between the rear cab of the GS4 and a 16" aluminum passenger car parked on the adjacent 072 curve. In that case the 2-10-4 would actually have more clearance than the Northern. But either a 2900 class Northern or a 2-10-4 should work anywhere on my layout, which is good to know.
