Which will be the hardest and most time consuming to forcibly enter for a railcar window?

The most difficult and time-consuming material to forcibly enter for a railcar window is Lexan. This is a type of polycarbonate material known for its exceptional strength and impact resistance. Lexan windows are designed to withstand high levels of force, making them a secure option for railcars where safety is a primary concern.

Forcibly breaking or cutting through Lexan requires specialized tools and techniques, which extends the time needed for entry. In contrast, tempered glass and safety glass, although they are designed to be strong, can shatter when sufficient force is applied, allowing for quicker access. Plexiglass is also relatively easier to breach than Lexan, as it is less robust and can be cut with standard tools.

Due to Lexan's high durability and its resistance to most standard forcible entry methods, it poses a significant challenge to rescue technicians, making it the hardest material to penetrate among the options provided.