Push-Pull
SEPTA Regional Rail operations mostly consist of electric multiple-units, but select rush-hour express trains utilize push-pull sets with Comet cars and ACS-64 electrics. SEPTA's ACS-64s arrived in late 2017 and replaced aging AEM-7s and ALP-44. Comet cars, some of which are pushing 40 years old at this point, were planned to be replaced with bilevel cars built by CRRC, but in 2024, after years of delays and a laundry list of problems with these new coaches, SEPTA canceled the order. The future of these push-pull trains is uncertain, especially considering recent SEPTA funding issues.