Union Pacific's policy on seal requirements can be found in MITA section 340. In order to be properly sealed, a Seal must be placed through the hasp furthest to the left on the right door. If the hasp in this location is inoperable, it is permissible to utilize the right hasp on the right door. Any container or trailer not sealed in accordance with these requirements may be rejected.
Theft-Deterrent Barrier Seals
Theft-Deterrent or Barrier seals provide the highest level of protection from unauthorized entry into intermodal containers or trailers. These seals are designed to prevent entry to the container with ordinary seal removal techniques, such as bolt cutters. Union Pacific recommends the use of a Theft-Deterrent or Barrier seal on all high-value loads.
Additional information on Theft-Deterrent seals can be found here:
Security Seals (Bolt Seal and Cable Seals)
Security seals are constructed of metal or metal clad cable, and are designed to provide minimal resistance to unauthorized entry into the container. These seals typically require bolt cutter for removal.
Additional information on Security seals can be found here:
Indicative Seals (Tin or Plastic Seals)
Indicative seals are only used to indicate whether or not a container has been opened. This type of seal does not provide any protection from unauthorized entry into the container. Indicative seals should only be used on loads that don't require protection from theft or contamination.