Do you work for the LIRR? If so, it's important to make sure the information you're adding is copyright-compatible with OpenStreetMap. If the timetable has a copyright notice on it, please ask LIRR management or lawyers for written confirmation that it's okay to use it as a source for OpenStreetMap.

If you can get written confirmation, we'd love to see photos or scans of the relevant info. Copyright-compatible sources are hard to come by in railway mapping, so this would be immensely helpful for us all.