What type of infrastructure is found at the Middletown Station?

The correct answer is high level interlock fence. This type of infrastructure is typically used in train stations to enhance safety by providing physical barriers that prevent unauthorized access to the tracks, ensuring that only authorized personnel and passengers can reach the boarding areas safely. High level fences also can help manage crowd flow and minimize accidents.

In terms of other options, a parking lot, pedestrian overpass, and bicycle rack may well exist at a train station like Middletown, but they do not specifically define the type of infrastructure as designed for safety and security on the platform itself. High level interlock fencing is particularly critical in areas close to the tracks, which is why it is emphasized in the context of station infrastructure.