NEW YORK (AP) — Amtrak trains were temporarily suspended Thursday afternoon from Philadelphia to New Haven, Connecticut, by a circuit breaker malfunction, the national rail service said.

The technical issue led to a widespread loss of power on the tracks between Penn Station in New York City and Union Station in Newark, New Jersey at around 3 p.m.

As a result, trains operating between Philadelphia’s 30th Street Station and New Haven’s Union Station have been are temporarily suspended until further notice, according to Amtrak.

The agency said crews were working to restore power but that significant travel delays were expected.

Earlier Thursday, Amtrak warned on the social platform X that soaring temperatures across a swath of the country may require trains to operate at lower speeds, resulting in delays of up to a hour between noon and 7:30 p.m. for the remainder of the week.