I agree with Notcom; the view is toward the south/southwest; based on the shadows it's late morning. The crossover track just behind and to the right of the engine is still there. Foundations for the long row of warehouses for potato storage on the right in the photo are still visible. The passenger station's still there; now it's Theriault Lawn Care. Engine 403 was one of the last steam locos on the Bangor and Aroostook, retired in 1956.

This is a fantastic composition. If it had been in color, the power of the photo would be lost.

The "Historic Aerials" overhead for 1953 shows a telltale trio of tanks -- say that three times fast ! -- on the eastern edge of the yard, which together with configuration of buildings, suggests the shot was taken from the vicinity of Hancock and Limestone Streets (they no longer intersect) looking south.

Here is the railroad terminal in Caribou, Maine today. You can't tell much from a Street View because of trees and vegetation. The terrain in the distance supports Jack Delano was facing north (top of photo). But I cannot find an arrangement in the tracks that match the 1940 photo, or where that arrangement might have been. I'm attaching a photo you can embiggen if anyone feels like figuring it out.

Stay mainly in their lanes?

Well... I think you'll have to wait a bit longer, and ride an open boxcar hobo style. Today, the passenger service from Boston only comes up as far as Brunswick. That's a good five hours south from up these neck of the woods. And keep yer eye out for moose young fella, especially at dawn or dusk ... they're much bigger than your car.