rendering glitch- front normals not visible

I’ve been having a little problem importing models into ue4 lately. Looks like in some of the imported models there is an artifact that makes the front faces invisible. By now this happened only with 2 models a long rail to go through all the map (image below) and a lamp. I thought it could be because of the near clipping but the bug also appears looking from far away and in game preview. The lamp is slightly different as the artifact for some reason only appears in the game and not in the viewer. Both models looked perfectly in the windows 3d viewer and in the modelling software (blender) so its probably a problem of the engine.