Tank car loading systems typically include a transfer pump, pigged piping system, some means of measuring the product being loaded and a loading arm to deliver the product into the tank car. In addition, a tankcar loading system may also incorporate product filters, vapor recovery, over-flow protection, grounding systems, tankcar indexing equipment, and tank car rinsing systems.

Tankcars can be top or bottom loaded, although top loading is by far the most common. The amount of product transferred can be determined volumetrically, using the ullage gauge in the tankcar or an in-line positive displacement meter, or by mass, using a Coriolis mass flow meter or load cells installed under the tank car. A pigged piping system can be used to ensure that the transfer pipeline is emptied after each loading operation, or to allow the metering system to be mounted some distance from the tankcar. In the latter case, the metering system discharges into the pigged pipeline and the pig clears the pipeline forward to the tankcar. Pigged piping reduces cross-contamination and helps minimize the number of pipelines required for the loading operation.

Loading systems can be fully automated and equipped with a variety of interlocks to improve operator safety, reduce operator error, minimize the chance of over-flow and otherwise enhance the efficiency of the operation. Card readers and operator terminals can be installed to communicate with plant control systems. This type of communication can be used to check inventories prior to loading, to ensure that the tankcar receives the correct product, to print bills of lading or certificates of analysis when the loading is complete, or to perform other administrative tasks.