There is a road from Whitaker to Gum Farm, but what I would do is walk down the road to the first crossing, which is at an S curve just below Whitaker. Shoot the next train here, it's the steepest part of the line and pretty open. Then follow the road down to point where the middle level of the switchback curves away into the classic Gum farm field shot. The engine will be facing downhill here, so this works as a down grade shot. Then I'd cut downhill to the lower level below the switchback and follow the tracks the rest of the way. Shoot the next train along Leatherbark Creek, or at Back Mountain Road crossing or one of the bridges over Leatherbark Creek. Rail miles from Whitaker to Cass is 3.8 miles, but by cutting across on the road and cross country it's probably about a 2 1/2 mile hike.
Michael Allen