CTA Pink Line train service resumed in the Loop after signal problems Monday morning near Clark/Lake halted trains for about four hours.

Starting about 8 a.m., Pink Line trains only operated between 54th and Polk, according to service alerts from the CTA. Trains started moving again shortly before noon, and normal service was restored with residual delays by about 12:16 p.m. The shuttle bus service between Polk and Ashland/Lake Pink Line stations was stopped about the same time.

Trains on the Brown, Orange, Purple and Green lines also experienced major delays because of the signal problems, the CTA said. Normal service was resuming with residual delays by 12:22 p.m., although Orange Line trains were still boarding on the Brown Line side of platforms in the Loop.