Third Edition

Gauging Device — a piece of equipment or a device
used to measure the level of liquid or vapor space in a
tank car tank, which may be a fixed gauge bar/outage
scale or T-bar attached to the top of the tank below the
manway nozzle (in nonpressure tank cars), or a magneticball,
fixed-length (telltale) tube, or an electronic device.
Hand Brake — A device mounted on railcars and
locomotives to provide a means for applying brakes
manually without air pressure. Common types include
vertical wheel, horizontal wheel, and lever type, sonamed
because of the configuration or orientation of
their operating handles.
Head — one of the ellipsoidal ends of a tank car tank.
Head Shield — A method of providing tank head
puncture-resistance by mounting a metal shield on the
end of a tank car to protect against punctures from the
coupler of another railcar. Head shields may be separate
attachments or may be incorporated into a tank’s jacket.
Heel — common term used for the product or residue
remaining in a tank car tank after it has been unloaded.
Insulation — a material, typically fiberglass or foam,
enclosed within a metal jacket, used to maintain or
moderate the temperature of the lading during
transportation. For cryogenic liquid tank cars, in
addition to a vacuum and insulation system, either perlite
or an alternating wrap of multiple layers of aluminum foil
and paper is used. Not all tank cars are insulated. Do
not confuse insulation with thermal protection.
Internal Valve — a type of bottom outlet valve located
inside a tank car tank to prevent damage in the event of
an accident.
Jacket — a metal covering (minimal thickness of 11
gauge) surrounding a tank car tank designed to protect
and secure the insulation and/or thermal protection
systems on a tank car. A jacket is not an outer tank.
Lading — the commodity being transported.
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