Power problems on Amtrak's Northeast Corridor continue to cause headaches for rail travelers despite millions spent to upgrade aging equipment.
Three incidents this week caused significant delays between Philadelphia and New York.
Amtrak says service was disrupted Thursday morning and afternoon because a computer problem prevented enough power from reaching trains.
Trains sat idle for several hours on Tuesday because of a transformer fire in New Jersey.
Amtrak has spent millions to upgrade old electrical equipment between New York and Washington, D.C., since 2002 and received additional funding in 2009. But spokesman Cliff Cole says it's impossible to completely prevent problems from occurring.
There have been seven disruptions caused by downed wires or voltage dips in New Jersey since March.