I appear to have come across an issue during my map making process. For whatever reason, several entities I place in Hammer do not appear in game. This issue is actually causing some maps to become unplayable due to a lack of symmetry. Occasionally, if I play more entities, the missing entities will appear in game, but other entities may disappear. Occasionally, certain entities, such as railroad tracks will flicker in and out of existence depending on the camera angle. I have tried deleted and replaying the entities, copying entities that do appear in game, and recompiling them map. None of these solutions has worked. I would be simply over joyed if someone would be able to help in any way.