What do the pavement markings at a railroad-highway crossing consist of, and what do they convey?

AAMVA CDL Manual, Section 10.4.2 – Warning Signs and Devices (Pavement Markings), pp. 10-7–10-8

Pavement markings act as a backup warning that remains visible even if a driver's attention is on the road surface rather than roadside signs, reinforcing the same slow-down-and-check message from a second angle.