Digitrax BD4N 4 Block DCC Occupancy Detector Terminal Track This is the Trucker Cap

This is the Trucker Cap Charcoal/Black by Axial

Series 6500-6557

And every Class 1 railroad has ponied up to buy them

Full separate air piping and brake equipment details

Digitrax BD4N 4 Block DCC Occupancy Detector Terminal Track This is the Trucker CapDigitrax BD4N 4 Block DCC Occupancy Detector FEATURES: Low cost, High sensitivity DCC block occupancy detection Adjustable resistance current detection section (DS) trip threshold 8A capacity, suitable for all scales and track wiring configurations Noise resistant and compatible with BDL168 sections On board status leds for stand alone occupancy and track power indication, expandable for optional LT5 or fascia mounted occupancy indicator leds Plug and