I agree with Matt's idea of catching them from the north side of the drawbridge, then heading west along Wawawai Road for at least one more good shot along the river. Totally doable. Been able to get him at the drawbridge, then again at the Hwy 128 bridge, then again down the river. Possible to get two decent shots before reaching the end of the chase road, but you'd have to hustle. This RA cover, taken where the road turns away from the track and river at Wawawai Park, was actually the fourth shot we managed to get during a chase that began back at the drawbridge.
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They cropped it from a hortizontal view that includes more of the river and canyon to the right, easily framed from the road crossing. There are other views, more interesting than this, if you take the time to drive into the canyon before the train leaves town and hike up onto the hillsides. Watch for snakes!!!

When fertilizer production is in full swing at Central Ferry (spring and early summer...correct me if I'm wrong), the work there can take long enough that you'd be able to shoot them arriving at Central Ferry, then backtrack out and reach the bridge west of Riparia ahead of him.