A railroad tanker car 10 with a fluid cargo tank 11 and a manway assembly 12 is disclosed. The manway assembly 12 includes a nozzle 17 having a nozzle sealing surface 24 and a cover 18 having a cover sealing surface 33. An attachment device 19 supplies a closing force to bias the cover 18 toward the nozzle 17. A fluid seal 51 prevents egress of fluids from and ingress of contaminants into the tank 11. The seal 51 includes a cover seal member 54, a nozzle seal member 55, and an expander 56 that forces the members 54 and 55 against their respective cover and nozzle sealing surfaces. The fluid seal 51 also includes a compression limiting carrier 52 with integral locating tabs 53 that locates the seal 51 and controls the compression of the elastomeric components of the seal 51.