There were two major mainline derailments involving the LIRR ore jennies. The first was in March, 1993 in Queens Interlocking. This blocked the Main Line and Hempstead Branch for several days. Coincidentally, once the derailment was cleaned up, the railroad was basically shut down due to an ice-storm/blizzard. When I was qualifying at NYAR, Bob McDermott from LIRR was giving us a lecture on Train Orders and brought in a video he took of the cleanup. You could see the snow starting to come down in the video. So not too many trains went through before everything shut down.
The second derailment happened just prior to NYAR assuming freight operations. I believe it was February 1997. Some rigging began dragging off one of the jennies somewhere between Nassau and Divide. Some track and infrastructure was torn up along the way, and when the train reached Divide Interlocking, everything went downhill. While there was trouble found with the equipment, a contributing factor was also placed on the engineer, who was traveling in excess of 10MPH of the allowable speed.
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