What is crashing and how does it differ from fast tracking?

Crashing adds resources to critical path activities to reduce their duration, such as adding overtime, hiring additional workers, or using more expensive equipment. It increases cost but compresses the schedule. Fast tracking performs critical path activities in parallel that were originally planned sequentially, such as starting construction before design is fully complete. Fast tracking does not necessarily increase cost but increases risk because parallel activities may need rework if earlier work changes. Both techniques compress the schedule but through different mechanisms.