After a hundred years of development, railways have been verified by what parts they use. Back to the question - there are galvanized rust-proof fasteners.
Many sections of the National Railway have been replaced with such elastic fasteners, and the subway is used on a large scale. The advantage of this type of fastener is that it does not need to be oiled and pressurized, which can indeed reduce the maintenance workload of the fastener. However, these characteristics will cause corresponding defects: for example, the buckle pressure of the rail cannot be adjusted; when the line is uneven, the conventional method of raising the rail height with the rail bottom rubber pad will be very difficult. If it exceeds 10mm, it is almost impossible to cushion it. In the fixed track bed section, it means that there is basically no room for adjustment, and it becomes a "pit". When you withdraw cash to the train, when the "pit" is relatively deep, the train will flip every time it passes. Of course, you can also use the method of smoothing the slopes on both sides to make the line smooth, so that the front and rear tens of meters must be raised or lowered in turn, and the workload will increase several times to ten times; Rail temperature stress will also be more difficult; finally, such elastic fasteners will break on their own, especially in the higher sections of the rail bottom pad. Regular inspections are required and timely replacement is required.