Most of this rail is achieved with plough, rebate and hollow moulding planes.
It helps to sketch out the profile.
Then with a marking gauge, pull the main lines along the rails. Or just set the plough plane, according to the sketch, and use that to define the widths and levels of the moulding.
A rebate plane will fashion the triangle, and a hollow moulder for the cove. Then a straight chisel to separate the triangle into a long row of hipped roofs. Chop out the background and then punch highlights.
Another moulding to run on the very short front feet.
Chop some tenons and mortices and a trial assembly.