[5] The tunnel from 23rd to 32nd streets was completed by 1933, but construction on the remaining segment was put on hiatus due to the Great Depression and World War II.

[5] The PRT went bankrupt in 1939 and was reorganized as the PTC,[6] which began building the rest of the tunnel in 1947.

[1] In 2022, SEPTA revised the project's budget to $31 million and estimated design and construction would be complete by 2025.

[8] The project now also includes the renovation of the existing platforms, new signage, lighting, and security cameras, as well as waterproofing improvements.

[8] Unlike most underground Market–Frankford Line stations, 34th Street has a single island platform.