The Interstate Commerce Commission, the New Jersey Public Utilities Commission, and the United States Army Corps of Engineers each conducted separate inquiries into the wreck, and all three found that the absence of a "dead man's control" was one primary cause of the accident. After the inquiries, the New Jersey Public Utilities Commission ordered the railroads to install such devices on all passenger locomotives operating in New Jersey. Some Jersey Central locomotives were already equipped with such devices, but this did not include the engine leading CNJ train #3314 on the day of the wreck. The railroad claimed that such a device was not always necessary, because all their trains had two crewmen in the locomotive cab. If the engineer was somehow incapacitated, the fireman would assume control of the locomotive.
An autopsy found that the engineer, 63-year-old Lloyd Wilburn, showed signs of hypertensive heart disease, but that he had died of asphyxia due to drowning. However, no reason could be found to explain why fireman Peter Andrew, 42, could not or did not stop the train. Investigators raised the wreckage and found no defect in the braking system on the locomotives and coaches; it was also determined that the signal system and derailing device on the bridge had functioned properly. Lacking further definitive evidence, it was presumed that the engineer had somehow become incapacitated in the cab and the fireman failed to take appropriate action to stop the train. The presence of a "deadman control" in the locomotive cab might have averted the catastrophe, and, while the I.C.C. only "recommended" the installation of these devices, the New Jersey Board of Public Utilities directed that the railroad install them in all of its locomotives.