Amtrak temporarily suspended all Acela Express service after cracks were discovered in the equipment during routine inspection. The passenger railroad has resumed more than half of the 50 daily train departures on its high-speed route using borrowed equipment. In addition to substituting Metroliner trains to fill gaps in the express service linking cities in the northeast, the passenger railroad leased locomotives and coach cars from agencies in Pennsylvania, New Jersey and Maryland. Amtrak initially cancelled all Acela Express runs mid-August after cracked yaw damper brackets, which prevent swaying at high speeds, were detected during a periodic maintenance inspection. If broken loose, a yaw damper could cause serious damage to the train’s underside. Amtrak is delaying a return to full service of its Acela Express service after additional hairline cracks were discovered on four high-speed Acela trains. “They are probably not new. These trains have been operating safely with these cracks,” Amtrak spokesman Cliff Black told Reuters. “But we like to feel an abundance of caution. We’re not going to run them with any cracks.” The Acela Express trains are manufactured by a consortium led by Bombardier, who is working closely with Amtrak to solve the defects. These newfound equipment defects join a host of other problems Amtrak has blamed for the high-speed service’s unreliable performance, for which Amtrak is considering making cuts to the service. Amtrak was already considering cutting back its Acela service due to reliability issues based on equipment problems. According to Amtrak, on-time performance between Boston, New York and Washington, D.C., dropped from 85% in January to 74% in July. During the same time, the number of trains cancelled or terminated en route rose from 10 to 35. David L. Gunn, Amtrak president, is said to be considering cutting Acela’s high-speed service between New York to Washington and concentrating it between Boston and New York. The rash of problems plaguing the $710 million Acela equipment include fluctuations in the train’s electrical system, a brake system freeze on one train and a variety of other problems, such as faulty valves and inadequate spare parts. In a statement, Bombardier said the trains’ problems were due to changes in the customer’s specifications for the equipment, not manufacturing problems.