Hopefully Mr. Long Island can answer your question right now...
Long Island Question of the Week:
I lost my camera on train to Mineola. Does the LIRR have a lost and found department?
Answer:
Yes, the MTA Long Island Rail Road has a Lost and Found department open M-F, 7:20AM - 7:20PM and Weekends, 7:20AM - 3:10PM. You may be able to get specific information about a recently lost item by calling 212-643-5228. They should be able to direct you to the main storage area for lost and found items, or direct you to a local facility based on the train line.
Hopefully a conductor or a commuter turned in your lost item. If you find something on the LIRR it is always a good idea to bring it to the attention of a conductor. In light of our National security issues, the public is urged to keep their eyes open and to report suspicious packages.