TriMet said it will again waive fares Thursday as it recovers from a major computer malfunction, but riders should expect delays in the afternoon as temperatures rise.

The agency continued to suffer intermittent network outages on Wednesday affecting its computer-aided dispatch and payment processing systems. The outages also rendered the agency's website and arrival-time tracker inaccessible at times.

The agency said Wednesday morning it would not inspect fares or expect payments that day. Late Wednesday night, it announced it would continue to waive fares through Thursday as it brings its payment systems back online and conducts tests.

The network issues have persisted since Saturday, when a planned system upgrade went awry. Agency officials blamed a faulty piece of hardware.

Meanwhile, the extreme heat has caused delays throughout the transit system, and temperatures are expected to top 100 degrees, according to the National Weather Service.

At 90 degrees, MAX trains will slow by 10 mph in high-speed zones, where trains typically travel up to 55 mph. The precaution is intended to prevent damage from drooping overhead wires or derailments cause by tracks deformed by heat.

At 100 degrees, MAX will travel no faster than 35 mph.

WES commuter rail, meanwhile, will slow to 30 mph if temperatures reach 95 degrees and suspend service if it reaches 105 degrees. In that event, stations will be served by shuttle buses, TriMet said.

Buses might also overheat or see crowding as riders try to avoid rail delay.

Because of a continued outage at its call center, the Lift paratransit service will provide life-sustaining trips only, the agency said.

-- Elliot Njus

enjus@oregonian.com

503-294-5034

@enjus