There are different types of sleepers required for different sections / elements of the track; Wooden, concrete and steel.
These may be subdivided into different types.
JS Rail and Civil can help you to determine which sleeper is required.
Wooden sleepers in track can get rotten if it happens that a lot get rotten over a long distance, one can do spot re-sleepering to keep the gauge widening.
Spot re-sleepering is to replace every fourth sleeper with a good or new sleeper. To do that one needs to use labour to replace it by hand and the same method is used to replace sleepers on turnouts.
Different kind of fastenings and clips are use on concrete sleepers .
The correct clip combination is to be use on straight and curves to make sure gauge widening is correct.