Comprehensive Glossary

A-I | J-Q | R-Z | Abbreviations

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Air unload aka Airing Off aka Blowing off : Unloading method using an air compressor, either mounted on the truck (Truck Air) or provided by the plant (Plant Air) to pressurize a tank for offloading, used for unloading dry bulk products from both pneumatictank trucks and PD railcars. Sometimes used on liquids instead of pumping from liquid tank trucks.

Axle weights: Truck’s weight at each axle (front, center, rear) added together for total weight, used when the whole truck is too big to sit entirely on the scale. More on weights here.

Back haul: The loading of a truck back towards its home terminal after it has already shipped out of the home terminal. (Because it is helpful for the company to get their drivers and equipment home, it can be lower priced.)

Bad-ordered Railcar: A railcar that is improperly loaded (often meaning overloaded), mechanically defective or has safety violations.

Belly Unloader aka Center Unloader: Liquid tank truck whose interior slopes down towards the middle of the tank to unload from the bottom.

Bill of Lading aka BOL aka B/L aka B of L: Paperwork that includes legal description of the product, amount shipped, special instructions and the origin and destination. Usually supplied by shipper, it serves as proof of delivery for billing.

Blind shipment: A shipment where one or both parties do not know who the other is. Often used when a third party is selling the product and doesn’t want the shipper and consignee to work directly with each other and cut the third party out. Requires a detailed blind bill of lading and extra care by the driver.

  • Blind pick up means the supplier doesn’t know who or where the product is being delivered to.
  • Blind delivery is when the recipient of the product doesn’t know who or where it shipped from.
  • Double blind is when neither know of each other.

Blowing Off: See air unload.

Border Broker: Customs broker who handles the paperwork at the Mexico and Canadian borders. The shipper typically selects the broker and always supplies the commerical invoice and other export documenation to the broker.

Bond: As in “shipping in bond,” if material is passing through the country and not altered in any way, it can be bonded to shield it from import taxes and fees.

Bob Tailing: When a tractor travels without the trailer attached.

Bottom Drop aka hopper bottom: Dry bulk trucks that can unload from hopper openings underneath the trailer. Can be a dump truck, railcar or a pneumatic truck (but not all have bottom drops). Grain hoppers always have bottom drops.

Boxcar: An enclosed, versatile railcar shaped like a box, rectangular with side doors.

Calibration chart aka strapping chart: Markings on the interior of a tank that help estimate the approximate volume of product in the tank. Accuracy is inexact!

Cancellation charge: Fee charged when a load is cancelled after the truck has been dispatched. Usually avoidable with 24 hours notice when cancelling. Also referred to as Truck Ordered Not Used or “TONU”.

Cat Walk: Walkway on top of tank truck to aid in access to the top of tank.

Carrier: Trucking company.

Caustic Wash: Tankwash using caustic cleaner, stronger than detergent.

Centerbeam railcar aka Spine car: A flatbed car with a vertical partition running the length of the car providing a structure to secure the load, usually with integral cables.

Center Unloader: see Belly unloader

Certificate of Analysis aka COA aka C of A: Lab report issued by shippers that gives a breakdown of the product, usually required by the consignee with delivery.

Certified Tank Wash: Official tank wash rack that issues certificates after washing as evidence of cleaning.

Chassis: Wheel base used to transport containers like ISO tanks.

Change-over wash aka Conversion wash: Thorough cleaning involving dismantling of pipes, changing of gaskets, etc., usually performed before dedicated service to a new product.

Circle Point: Certain cities within the Rand McNally mileage guide for which the mileage is printed to other circle points as a time-saver. Then additional mileage from non-circle points to a circle point can be added on by the user for total mileage.

Clean dry and odor free: Lingo for a clean liquid tank ready for service.

Coded Tank: System of coding to differentiate between different types of liquid tanks.

  • MC 307 and 407 coded tanks are the most common chemical tank, though they can be used in food grade service. Have 3/16 inch thick stainless steel walls and internal valves.
  • MC 304 tanks aka sanitary tanks or noncoded tanks, are food grade with no internal valves for better cleaning (due to this, not suitable for products like alcohol and unable to air unload).
  • MC 312 tanks are less common, heavy duty tanks generally used for acids.

Coiled and Insulated: Specialized feature for a liquid tank truck where coils run through the insulation to facilitate steaming, and sometimes Heat in Transit.

Collect: A billing term which usually means the receiving party will be billed, and sometimes means payment will be collected by the driver before unloading.

Compartmentalized Tank Truck aka compartment tank: A liquid tank separated into 2-5 compartments so that different products may ship at the same time.

Compression release engine brakes aka Jake Brakes aka engine brake: Supplemental braking system on large vehicles, using engine compression for braking. The loud noise they produce has necessitated regulations on their use in noise sensitive areas.

Consigned to: Party receiving the product.

Consignee: Receiver of product, delivery site.

Container: Box-like shipping vessels used to ship by rail and highway (loaded onto a chassis), or on a freight ship. International containers conform to ISO standards and are either 20′ or 40′ long. Domestic versions are designed exclusively for rail and highway use, are lighter and can be up to 53′ long.

Container Drayage: The shipping of a container on a chassis.

Contamination aka Contaminated load: When a bulk product is delivered with a foreign substance present in the intended product. The source of the contamination determines the liable party.

Conversion Wash: See Change-over wash.

Cubic Feet aka CFT: The way volume capacity of dry bulk tanks is measured. Smaller tanks = 1000-1100, and larger, common “high cube” tanks = 1500-1600. High cube trailers over 1600 cft are rare and specialized.

Deadhead: The mileage driven without a load, usually en route to pick up a product.

Dedicated: Equipment in exclusive use, either by one customer or for one product (or both).

Demurrage: The time a truck is detained at loading or unloading beyond the “free” time (which is usually 2 hours, with the clock starting when the truck enters the gates – unless it is early – and ending when it’s released). Charges are accrued, usually at an hourly rate of $40-75 per.

Detergent Wash: Tank wash using detergent.

Double Blind: See blind shipment.

Double Conical: Interior shape of a center unloading liquid tank.

Double Stacked: Pallets stacked on top of each other in a van for maximum use of space (must defer to weight restrictions).

Dunnage: Materials used to secure, brace and protect (“block and brace”) cargo as well as the cargo vehicle’s hold from damage during shipping. Common dunnage materials: boards, air filled bags, cribs, etc.

Drayage: See Container Drayage

Drumming Nozzle: Special equipment for unloading liquids directly from the tank into smaller containers, like drums or totes.

Dust Collector: Special filter/trap for containing dust created by airing off or vacuuming dry, fine products

End Dumps: BIG tractor trailer type dump trucks (vs smaller construction style ones) that unload via a gate at the end. Can be tarped.

Engine Brakes: see compression release engine brakes.

Federal Highway Administration aka FHWA: US DOT agency involved in the design, construction and maintenance of the nation’s highway system. The FHWA Office of Motor Carriers was the predecessor to the FMCSA.

Federal Motor Carrier Safety Administration aka FMCSA: US DOT agency whose mission is to prevent commercial motor vehicle-related fatalities and injuries through licensing, safety initiatives, promoting awareness, and by enforcing adherence to safety, hazardous material handling and other regulations.

Flash Point: Minimum temperature at which a substance will give off flammable vapor that could ignite if in contact with a spark or flame.

Flatbed truck: Flat trailer without sides, usually used for lumber and steel. Can be tarped.

Flat car: Open, flat railcar.

Food Grade: Refers both to edible products meant for human consumption and to tanks that are coded or maintained to handle edibles.

Food Grade Wash: Special certified tank wash that is thorough enough for edibles.

Frost Laws: Canadian law limiting legal vehicle gross weight to 20% less than usual during severe winter months to protect roads from damage. Dates vary.

Fuel Surcharge aka FSC: A fluctuating cost (usually a percentage) applied to loads to offset high fuel prices. Carriers each have their own formula to calculate this, based on the national average of diesel fuel week to week.

Gondola railcar: Open top railcar with low sides, typically carrying bulk goods or steel.

Gooseneck Trailer: Special low, open trailer used for shipping over-tall items like machinery.

Hazard Class: A group of materials the DOT has identified as sharing the same hazardous characteristics when transported (flammable, corrosive, etc.). An alternative numerical classification system

Hazardous Material aka HM: Substance capable of posing an unreasonable risk to health, safety, or property when handled or transported commercially.

Hazardous Material Regulations aka HMR: 49 Code of Federal Regulations (CFR) Parts 100-185 detail the regulations for handling materials identified by the PHMSA to be hazardous.

Head haul: Lingo for a route that originates from the “home” terminal area and delivers away from it, therefore it’s usually more expensive than a back haul.

Heat In Transit aka HIT aka In-transit heat: Special equipment that helps maintain, but cannot raise, loading temperatures of liquid products, typically ones that thicken too much if they cool. System can be coil-based with the truck’s radiator fluid circulating through the coils while it’s being driven. But not all coiled trailers can run heat in transit. Usually some heat is lost, especially when the truck is not running and when the climate is very cold. Not always an effective substitute for steaming.

Heel: Leftover product stuck to the tank after unloading, necessitating heel removal and disposal, usually by a tankwash facility. Can get pricey – $3-15 per gallon typically.

Heel Disposal Charge: Charges necessitated by a product heel, above.

High Cube trailer: Dry bulk trailer whose volume capacity is 1500 cubic feet or more.

Hopper Bottom: See bottom drop.

Hopper car: Railcar, open at the top or enclosed, with bottom drop openings, used for bulk, loose goods.

Hose: Trucks typically carry 40 ft of hose, and sometimes food grade trucks don’t carry any. For liquids, a hose size of 2″ hose is common for chemicals, 3″ for food grade. 4″ is the standard dry bulk size. Extra hose is often an extra charge.

Hoses Capped and Bagged: Lingo for a special sanitary measure (usually for food grade or pharmaceutical grade products) where hoses are capped then sealed in plastic bags by the tankwash.

Hours of Service aka HOS: The legal hours that a driver can work. Current regulations allow for 14 hours max per day for the driver to be ‘on’, only 11 of which can be driving hours, with 10 hours off per day. Weekly maximum is 60 hours per week with a 34 hour break before the next 60.

Hundred Weight: A rate structure, mainly for liquid bulk, where freight is billed per every 100 lbs, usually on a minimum of 44,000 lbs or 48,000 lbs. (Example: $2.50 cwt would be 2.50 times 440 for 44,000 lbs, so $1100.)

Intermodal: The interconnectivity of more than one mode of transportation (ie, rail to truck). Intermodal facilities serve to switch product from one mode to another.

Internal Valves: Valves inside a liquid tank in between the tank and the unloading outlet. A safety feature to prevent leaking.

Interstate Commerce Commission aka ICC: Former government agency that regulated rates and other trucking industry concerns. Replaced by Federal Motor Carrier Safey Administration aka FMCSA.

International Organization for Standardization aka ISO: Non-governmental developer and publisher of International Standards from a network of 164 institutes (one per country) and a Central Secretariat in Geneva, Switzerland that aims to create a consensus that meets the needs of both business and society.

ISO 9000: Chemical industry safety program instituted by ISO to improve safety.

ISO Tank: Liquid bulk shipping container, 20 ft. long, that can typically hold 5500 gallons and can ship by truck (on a chassis), by rail (“piggy back”, on a flatbed car) and by container ship. A crane is required to move them.


Jake Brake aka Engine Brake: See compression release engine brakes.

Kosher Certificate: Documentation that a particular tank (identified by a tank number) has been blessed by a rabbi, making it suitable for kosher goods.

Kosher Tank: A food grade tank that has been dedicated to kosher service and is regularly blessed by a rabbi.

Last Three Products List: Lingo for a list on carrier’s letterhead showing the last three products hauled by a specific trailer (trailer number listed), to ascertain its suitability for a pending load.

Layover: When a truck and driver is detained overnight to load or unload the next day. A fee is usually charged.

Less than Truck Load aka LTL: Van shipment of a partial load. Will likely ship with other products on board.

Line Haul: The rate based on the actual loaded miles for a given shipment.

Load and Go: Lingo for a short run that picks up and delivers the same day.

Loading Temperature: The temperature at which the product is loaded. Can be critical for viscous liquids to flow at delivery.

Log Book: Legally mandatory record drivers keep of their hours of service. Police can shut down a truck and impose fines if they find the book has not been updated or if it shows too many hours.

Low Boy: See gooseneck trailer.

Manhole: Opening on top of a tank allowing access to the inside. Sometimes products are loaded through the manhole.

Manifest: Shipping paperwork serving as inventory of cargo and description of route, similar to bill of lading.

Manifest / Uniform Hazardous Waste Manifest aka UHWM: Shipping document required by the US DOT and the EPA to accompany hazardous waste shipments, specifying all DOT required information: proper shipping name, hazard class/division, ID No. and packing group. (49 CFR 172.205)

Material Safety Data Sheet aka MSDS: Government regulated chemical and hazard breakdown of a product, required to accompany any hazardous shipment (as defined by the DOT).

Max legal load: Maximum gross weight of the truck and its load. In most states, it is 80,000 lbs (about 24 tons for product, with the weight of the truck itself considered). Can be as high as 99,000 lbs in the US and varies up to 138,000 lbs in Canada and Mexico.

MC Authority or MC Number: US Government registration number give to every trucking company and logistics broker.

Metric Ton: 2200 pounds (vs a US ton of 2000 lbs).

Mileage Rate: Rate calculated on mileage and expressed as dollars per mile.

Minimum Delivery Temperature: The lowest temperature a (liquid) product can be and still be able to flow at delivery.

Muffler: Special muffler for pneumatic tanks to lower noise during ‘airing off’ , often requested for residential areas.

National Tank Truck Carriers aka NTTC: Association of tank truck industry members that acts as an educational resource and forum for discussion of industry issues and also serves to represent those interests before government entities and the public.

Net Weight: Weight of product alone. See weights for more.

Non Code Tank aka Noncoded Tank: MC 304. See coded tank for more.

Not Otherwise Indexed by Name aka NOI: Designation that can be used in place of the specific chemical name on a bill of lading for nonhazardous materials.

Occupational Safety Hazard Association aka OSHA: US government agency that regulates workplace safety risks, regulates safety measures and oversees compliance.

Off Spec Product aka Off Specifications: Product that doesn’t meet the customer’s specifications due to any number of reasons: color, clarity, moisture level, chemical composition, smell, contamination, etc. Can be reason for rejection of delivery.

On the Floor: Van lingo for materials loaded on the floor only, not stacked.

Out of balance railcar: A railcar that has been loaded unevenly or whose load was not secured properly so product has shifted and now poses a risk for derailment.

Overloaded aka Overweight railcar: A railcar whose gross weight exceeds the maximum limit for a given rail line or specific area, and therefore poses a risk of damage to the rail or derailment.

Over the Road aka OTR: A carrier or driver that ships from one region to another or handles shipments of 500+ miles.

Placards: Diamond shaped signs posted on a tank, van or railcar that show a specific hazard (corrosive, flammable, explosive, etc), usually supplied by shipper if required.

Pallet aka skid: Platform, usually wood, that serves as a base to aid forklift handling, often with their product shrink wrapped on them. Shipped via vans, railcars and containers, though material is often taken off pallets when loading into containers to save space and weight. Standard size is 40″ x 48″ or 4′ x 4′, weighing about 50 lbs with a capacity of about 2000 lbs. A 40′ container fits 18-40, a 48′ van fits 22-24 “on the floor” or 44 if double stacked, and a 52′ van fits 26-28 on the floor.

Piggy Back: Container or trailer shipped by rail (on top of a flatbed car).

Pipeline and Hazardous Material Safety Administration aka PHMSA: US DOT agency that develops and enforces regulations to reduce the risk to people and the environment from the transportation of hazardous materials by pipeline and other modes of transportation.

Pneumatic Tank: Dry bulk tank that is unloaded by pressurizing it to force the product out of the tank (airing off) through hoses.

Prepaid: When the shipper or third party is billed the freight charges.

Pressure Differential Railcar aka PD Car: Enclosed railcar for dry bulk products that can be pressurized to force the product out through hoses, like a pneumatic tank. Much like a hopper car without bottom drops.

Pressure Relief Valve: Special valve found on food grade tanks (usually MC 304’s) designed to release pressure build up in the tank from the product. It makes air unload impossible.

Prior Commodities List: List of the last (or last few) products hauled in a tank truck, used to avoid product incompatibility issues with sensitive products. For example: a sugar shipper may have a restriction that the last 3 products hauled cannot have been oils.

Proof of Delivery: Paperwork, usually the bill of lading, signed by the consignee to acknowledge the delivery, thus very important for invoicing.

Pump: For unloading liquid products. Can be carbon steel (which could rust, so not appropriate for food grade or USP) or stainless steel which doesn’t rust.

Qualcom: Satellite tracking service that can locate participating trucks.

Quick Couplers aka Quick Disconnect: Type of hose fitting which can differ in size (ie 2 inch quick coupler).


Rand McNally: Mileage system accepted by the industry (accurate within 10%), in book or computer format. See circle points.

Rear Unloader: Liquid tank truck that unloads from a rear outlet, versus a center unloader.

Reducers: Hose fittings that connect a larger hose to a smaller outlet (ie, 3″ to 2″ reducer connects a 3″ hose to a 2″ hose).

Rejected Tank: Tank that fails pre-loading inspection for cleanliness. Plant may allow tank to re-wash and be re-inspected.

Reefer: Refrigerated van.

Roll off: A box container that can be left on site, separate from the truck.

Rubberlined Tank: Special lined tank for hauling products that are very corrosive to metal tanks (like acids). Usually dedicated.

Sanitary tank: Food grade tank, MC 304. See coded.

Scully: Equipment used to ground a truck during loading or unloading to prevent static electricity from building up.

Shipper: Actual supplier of product.

Shipping Class: Mostly for van shipments, it is the chemical class for a product shipped as determined by the DOT. Higher classes are more costly to ship.

Shrinkage (not a la Seinfeld!): Product loss caused by handling, such as from transferring material from one mode of transport to another, packaging, etc.

Shrink Wrapped: Plastic wrap used to protect and secure bags on a pallet.

Sighting Code: Railroad codes for CLM aka car location messages. See here for a key (outside link).

Skid: See pallet.

Skin Tank: Lingo for non-insulated tank truck.

Spec aka Specifications: A product’s composition (required by a customer and tested by a lab). Also, see off-spec.

Split Load: See compartment tank.

Split Weigh: When a truck’s axle weights are taken because the truck is too big to sit entirely on the scale.

Standard Carrier Alpha Codes aka SCAC: A four letter code that is maintained by the National Motor Freight Traffic Association, used to identify the many carriers (ours is TDLD). The NMFTA no longer offers a free listing of the codes on their site.

Standard Industrial Classification Code aka SIC Code: Four digit government code indicating the industry a business operates within. Sometimes used in the paying of vendors.

Standard Transportation Commodities Code aka STC Code: Government code identifying chemicals, their shipping hazards, and appropriate shipping equipment and handling procedures.

Steam or Steaming: Method of heating a liquid product so it will flow at delivery. Steam is circulated through special coils within a tank’s insulation jacket, usually performed at a wash rack or terminal for an hourly rate. Raises product’s temperature about 5-10 degrees per hour. There is the risk of scalding, burning or darkening some products.

Surface Transportation Board aka STB: Governmental agency that replaced the Department of Transportation aka DOT.

Team: Two drivers for one truck, meaning one can sleep while the other drives to deliver faster while still adhering to HOS.

Third Party: Parties other than the shipper, consignee or carrier (ie, a chemical broker or third party logistics provier, below.)

Third Party Logistics Provider aka 3PL: A firm that provides outsourced logistics services for part or all of their supply chain management (TDS is a 3PL). For more on the different types of 3PL’s, see here (outside source).

Ton, Weight: 1. Short ton = 2,000 pounds (most common in US) 2. Long ton = 2240 lbs 3. Metric ton = 2204.68 lbs (most common in the steel industry)

Tote: Shipping containers (mostly for liquids) small enough to fit on a pallet.

Towaway: When a trailer is moved from one location to another to be left there.

Trailer on a Flatcar aka TOFC: Shipping container on either a chassis or railcar.

Transfer Station: A yard where product is transferred from rail to truck, inter-modally.

Transportation Intermediary Association aka TIA: Organization “Third Party” businesses belong to.

Transportation Security Administration aka TSA: Governmental agency under the Department of Homeland Security, responsible for regulating security within the transportation industry.

Transportation Worker Identification Credential aka TWIC: A tamper-resistant credential issued as a security measure by the TSA and US Coast Guard to all merchant mariners and others requiring unescorted access to secured port areas and vessels.

Truck Ordered Not Used aka TONU: Cancellation Charge.

Uniform Hazardous Waste Manifest: see here.

United Nations Number aka UN Number: A four digit number used worldwide to materials considered regulated aka hazardous (ie, UN# 2319).

US Pharmaceutical Grade aka USP: Materials regulated for human skin contact or ingestion. Similar restrictions as food grade.

Vacuum Pneumatic aka Vac tank aka Vacuum unit aka self-loader: A very specialized (and thus expensive) dry bulk pneumatic tank equipped with a vacuum apparatus that can suck product out of a vessel to load itself. Very useful for offloading dry bulk goods on railcars.

Van: Truck with box trailer for packaged goods (shaped like a moving van but generally bigger).

Vapor Recovery System: Specialized equipment for liquid tanks that captures vapors from a product during loading or unloading to prevent them from escaping into the environment (more common in the chemical industry).

Walking Floor: Van industry lingo for a van trailer whose floor is divided into three sections which alternately go forward and backward to facilitate easier unloading.

Weights: A truck’s weight, loaded and unloaded to determine a loose product’s weight.

Gross Weight: Total weight of truck and load.

Tare: Weight of the truck empty.

Net Product weight: Gross minus Tare.

Weight Ticket: A slip given by a certified scale showing the weight of the truck, thus serving as proof of the product’s weight.

Yard Trucks: Tractors used to move trailers within a company’s property that are usually smaller, lighter and more nimble than road tractors. Also called: Switchers, Hustlers, Mules, Yard Dogs, and Yard Goats.


48 102: Regular van size, 48 ft x 102 in.

53 102: Large van, 53 ft x 102 in.

ADC: Automatic Data Capturing. Technology that uses electronic sensors to automatically identify and record events such as location, temperature. ie Bar codes, 3d tags, voice recognition and other RFIDs

CFT: Cubic feet. More here.

COA, C of A: Certificate of Analysis.

CWT: Hundred weight.

DB: Dry bulk.

DOT: Department of Transportation.

FG: Food grade.

FHWA: Federal Highway Administration.

FMCSA: Federal Motor Carrier Safety Administration.

FSC: Fuel surcharge.

HIT: Heat in transit.

HM: Hazardous Material.

HMR: Hazardous Materials Regulations.

ICC: Interstate Commerce Commission, now defunct.

ISO 9000: See here.

LTL: Less than Truckload. More here.

MC: Motor Carrier, trucking company.

MC 307, MC 407, MC 304, MC 312: See coded tank.

MSDS: Material safety data sheet.

NOI: Not otherwise indexed by name.

NTTC: National Tank Truck Carriers, an industry recognized organization many bulk trucking companies belong to (as we do).

OSHA: Occupational Safety Hazard Association, a government agency regulating work safety risks.

PHMSA: Pipeline and Hazardous Material Safety Administration.

PD Car: Pressure differential railcar. More here.

PPE: Personal Protection Equipment. Safety equipment specific to product and job (ex: hard hat, steel toed boots, safety glasses/goggles, particulate respirators for dry bulk, work gloves, safety suits, etc.

RFIDs: Radio Frequency Identification. Technology that communicates via radio waves to exchange data between a reader and a “tag” attached to an object. Passive example: an unpowered bar code which a reading device identifies. Active example: a battery operated tag which sends a signal to a reader within range.

SIC Code: Standard Industrial Classification code.

SS: Stainless steel (referring to pump or tank).

SSI: Stainless steel insulated, referring to tanks.

STB: Surface Transportation Board, replaced the DOT.

STC Code: Standard Transportation Commodities Code.

T/L: Truckload, referring to a full van shipment.

TOFC: Trailer on a Flat Car.

TONU: Cancellation charge for a truck.

TWIC: Transportation Worker Identification Credential.

UHWM: Uniform Hazardous Waste Manifest.

UN Number: United Nations Number, to i.d. chemicals.

USP or USPG: United States pharmaceutical grade.

*Disclaimer: This glossary is intended only as a helpful guide. Total Distribution Services, Inc. (TDSI) does not warrant or assume any legal liability or responsibility for the accuracy, completeness, or usefulness of any information disclosed.