Amtrak expected to release evidence Monday in train derailment

PHILADELPHIA (WPVI) -- Investigators are set to release evidence Monday that could reveal why an Amtrak train derailed last May.

Eight people were killed and more than 200 injured in the city's Port Richmond section.

VIDEO: Engineer declines to give statement to police

The release of the information constitutes the first major development since the National Transportation Safety Board pointed to excessive speed as a key factor.

Investigators say the train was going more than 100 miles per hour as it approached a curve with a speed limit of 50 miles per hour.