Profile: Midland Manufacturing Corp. is a manufacturer of valves and level measurement devices for railroad tank cars, marine barges, and ISO containers that transport a wide variety of general purpose and pressurized hazardous chemicals. Our pressure relief valves are used in a wide range of applications and provide the additional security of being a re-closing pressure relief device. Internal and external valve designs are available in pressure ratings from 75 psig to 165 psig, and flow rates up to 35,527 scfm. O-ring seals are easily replaced, and can be used with a diverse range of commodities to maximize the in-service life of every tank car.