Union Pacific Railroad will introduce a US$500 peak season surcharge on low-volume shippers from June 21, reflecting rising truckload rates and fuel costs that are shifting freight onto rail, reported New York's Journal of Commerce.

The surcharge applies to shippers moving fewer than 250 loads annually in UP-owned EMP and UMAX containers originating in Chicago, Laredo, and California. Larger shippers will be exempt, but the move highlights tightening domestic container capacity.

UP stated that demand for EMP and UMAX containers has risen sharply, particularly in Southern California, where volumes jumped more than 20 percent year over year. The railroad has been returning idle containers to service after years of downturn.

Domestic container moves grew nine percent in March and April, according to the Intermodal Association of North America. May figures are expected within 10 days, with continued high-single-digit growth anticipated.

Sources told the Journal of Commerce that UP's early surcharge is the first since 2021. Analysts warn that more shippers could face charges if demand continues to outpace supply, especially with international cargo frontloading ahead of July tariffs.

Earlier this week, UP raised spot prices across more than 100 intermodal lanes, effective June 17. Average increases are nearly 12 percent, with some Southern California lanes rising up to 25 percent.

Shippers are already paying more for intermodal capacity than they were six months ago. Some 2026 contracts are being rejected by providers, forcing companies to seek higher-cost alternatives and underscoring the strain on rail capacity.