SEPTA now operates (along with the Broad Street subway) all "Owl" service using buses, but similar to the old "Owl" trains, they run between 69th Street and Frankford Transportation Center on a slightly more frequent 15-minute interval. During the late 1980s and early 1990s, some M-3s were regauged to work on the Norristown High Speed Line during the delivery of the N-5 cars. In the early 1990s, the Market–Frankford Line was in need of new rolling stock. The M-3 cars were approaching the end of their expected useful lifespan, as well as being increasingly scrutinized for their shaky ride quality and lack of air conditioning. SEPTA placed an order for 220 new rail cars, each costing $1.29 million. These cars, designated Class M-4, were manufactured by Adtranz (now Bombardier Transportation) in Elmira, New York, and delivered between 1997 and 1999. These cars are equipped with AC traction motors, air conditioning, LCD signage, and automated announcements. All of the M-3 cars were retired after the last of the M-4's entered service, with five of the former being converted to work cars. The five remaining M-3's were later retired, with M-4 cars 1033 and 1034 replacing them for work service, and the last of the remaining M-3's had been scrapped by 2005. Two of the M-3's have been preserved, cars 606 and 618 at the Pennsylvania Trolley Museum and the Seashore Trolley Museum, respectively. These cars represent the only preserved examples of Market-Frankford line rolling stock. In February 2017, SEPTA temporarily removed about 90 M-4 cars from service after inspections revealed cracks and signs of fatigue in load-bearing bolsters and associated components. SEPTA has begun the process to obtain a new M-5 fleet to replace the very problematic M-4 cars. Accidents On December 26, 1961, one man died and 38 others were injured when four cars of a train derailed while rounding the curve just north of York-Dauphin Station. The deceased was identified as Earl Giberson, a 64-year-old man. On March 7, 1990, four people died and another 162 injured when the rear three cars of six-car train #61 derailed after leaving 30th Street Station westbound at 8:20 a.m. It is believed that one of the traction motors dropped out of the rear truck on the third car (M3) somewhere between 15th and 30th street stations, and it became entangled in a switch immediately upon leaving 30th street station. The front truck