NEW ORLEANS (AP) — Flood damage closed a rail bridge just west of New Orleans, delaying freight and forcing Amtrak to shuttle passengers by bus at the Louisiana end of the City of New Orleans’ twice-daily route.

A 26-foot span was damaged, apparently when debris hit a pier supporting the bridge over the Bonnet Carre Spillway, about 13 feet from where the bridge changes from wooden trestles to concrete, Canadian National Railway spokesman Patrick Waldron said Tuesday.

Waldron said inspectors found the damage after an Amtrak engineer reported a rough ride there Sunday.

That outbound train, with a 69-foot-long, 134.5-ton locomotive and seven 85-foot-long, 75.5-ton coaches, had a crew of about 10 and reservations for 191 passengers, Amtrak spokesman Marc Magliari said.

An aerial photograph by WVUE-TV, taken after repairs had begun, showed a 26-foot gap under the rails. Waldron said he did not know whether the trestle was removed for repair or replacement, or was missing when the inspector arrived. Neither he nor Magliari would say whether the train could have made it safely across a missing trestle, saying that was speculation.

Magliari said he was told Tuesday that buses between Hammond and New Orleans will be needed at least until Thursday. The City of New Orleans runs between Chicago and New Orleans, with stops in Kentucky, Tennessee and Mississippi. The Los Angeles-New Orleans Sunset Limited uses the Huey P. Long Bridge; neither it nor the Crescent, which runs between New York and New Orleans, is affected, he said.

Amtrak has only had 1 1/2 days of normal service on the City of New Orleans since April 26, when floods closed the 219-mile stretch of rail from Carbondale, Ill, to Memphis, Tenn. Amtrak had no alternative for that stretch, which reopened May 21.

About eight Canadian National freight trains also cross the Bonnet Carre bridge each day, Waldron said.

“We’re working on alternative routes but there will be some freight delays,” he said. Other routes include one between Baton Rouge and New Orleans that was reopened Monday after being closed because tracks on levees were covered with sand bags. Temporary floodwalls at Memphis covered the track until recently, he said.

Waldron said CN had a parallel route for freight when the track across from Cairo, Ill, was flooded, but Amtrak couldn’t use it because it had no stations.