CONCORD (CBS SF) — BART removed three of four cars from an out-of-service train that derailed in Concord during the Friday evening commute, prompting buses and a shuttle train to stand in for normal train service between four stations on the Pittsburg/Bay Point line.

Cranes Saturday morning hoisted the third of four cars involved in the derailment off of elevated BART tracks in Concord, and the fourth car was expected to be removed by 1 p.m., agency spokesman Jim Allison said.

Flatbed trucks were bringing the cars to a BART maintenance yard. Once all of the cars are removed, crews will replace cables and other parts of the trackway damaged by the derailment and will inspect the rails for safety, the spokesman said.

Allison said the trackway sustained “significant” damage in the derailment, which happened as an out-of-service train was leaving the Concord station around 6:30 p.m. Friday.

No conductors were injured in the derailment.

BART officials continue to investigate what caused the derailment, which agency spokeswoman Alicia Trost said happened as the train traveled over a switching mechanism known as an interlocking.

Full repairs to the trackway weren’t expected to be completed before Saturday afternoon, according to Allison.

Until then, BART was running bus service between the Pleasant Hill and Pittsburg/Bay Point stations as well as a shuttle train between the Pittsburg/Bay Point and North Concord stations.

Those planning to take BART from Contra Costa County toward San Francisco Saturday were encouraged to take trains to and from the Pleasant Hill station to avoid significant delays.

Allison said BART employees were on hand at each of the four affected stations to answer travelers’ questions Saturday.

© Copyright 2014 by CBS San Francisco and Bay City News Service. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.