1. A pressure indicator for a railway car comprising: a fixed assembly having lower and upper cylindrical portions, said lower cylindrical portion engaging an opening in a pressurized portion of a rail car; said lower and upper cylindrical portions each having transversely extending flanges holding therebetween a flexible diaphragm; a movable assembly at least a portion of which is mounted within said fixed assembly comprising an inner cylindrical portion and a color coded rod portion viewable from the side of the car removably affixed to said inner cylindrical portion; a coil spring mounted within said indicator surrounding said rod portion and engaging said fixed upper cylindrical portion and said inner cylindrical portion; said upper cylindrical portion having a bleed opening therein to avoid pressure buildup and a downwardly extending tubular portion containing an elastomeric seal; said flexible diaphragm engaging said inner cylindrical portion and adapted to move in response to pressure changes in said railway car whereby an increase in pressure will move said assembly against the bias of said coil spring with said rod passing through said seal and indicate pressure change in said car to a viewer standing near the car.