These heavy duty guardrails protect the pipeline below from the miscalculations of drivers passing overhead. Don't recall ever seeing guardrails this skookum, even on high bridges. But a hole in the pipeline - even a small one - could result in millions of dollars in damage and lost revenue.
These orange signs with black numbers are pipeline mileposts. In this case, it is above a buried portion of the line, but in other spots the mileposts will be attached to a VSM (Vertical Support Member) where the pipeline is aboveground. By adding 2 to the miles shown, you can usually get a pretty good idea how many more miles to Deadhorse.
The yellow signs with black numbers designate, as far as I can ascertain, a crossing of some sort, such as under a river or stream. The first number indicates the next pump station upstream, and the second seems to be the numerical order of the crossing from the pump station on downstream. This one is on the downstream side of the Kanuti River at Mile 105.7.
Pump 4, the highest in elevation of all the pump stations, sits atop a low hill near the mouth of the Atigun River valley.
This shot shows that the pipeline is not a straight shot to anywhere.
Taken from around Mile 300 facing north, with Slope Mt. on the left, the pipeline appears to run straight as a die.
Taken near Mile 29 looking north, this photo shows how the pipeline goes up, over, down, and around as it follows the contours of the earth in this hilly region.
This maze of pipeline, with radiators atop VSM's standing out above the vegetation, can be viewed from MP160 looking northward.