Installing 
Infrared Detectors
These step-by-step photos supplement the NightScope™ Infrared Detector Product Manual.
For applications where the Infrared Detector does not need to be hidden (detecting trains in a helix, for example), you can skip all of this. Simply drill a 3/8" hole and glue the Infrared Detector in place.
For a simpler yet still hidden installation, see the alternative installation page.
Installation Diagrams

HO Scale installation (Figure 1 in the Product Manual)

Suggested N Scale installation
For N Scale, angling the LED and Sensor hole locations will minimize the number of ties to remove.
Step-By-Step Photos
Installing a NightScope™ Infrared Detector: HO track on Homasote on 3/4" plywood roadbed. Step numbers correspond to the installation steps in the Product Manual.
Start with the Pilot Hole

Step 1: Center point for 1/16" Pilot Hole marked.

Step 2a: Drilling...

Step 2b: Pilot Hole done.
Blind Drill the Detector Body Hole from Below

Step 3a: A thin wire measures the depth of the Pilot Hole.

Step 3b: Hold the wire end flush with the bottom of the hole. Pinch the wire flush with ballast top to mark the depth.

Step 3c: Depth of hole...

Step 3d: Mark Pilot Hole depth on convenient surface, like the adjacent roadbed.

Step 3e: To blind drill within 3/16" of surface, subtract 3/16" and mark.

Step 3f: Align 1/8" drill bit and wrap with masking tape to mark depth.

Step 3g: Blind drill from bottom following the Pilot Hole.

Step 3h: Not quite deep enough...

Step 3i: Stop when tape touches the surface.

Step 3j: Follow 1/8" hole with 1/4" and then 3/8" bits, both taped for blind depth.

Step 3k: Pilot Hole visible in the middle of the Body Hole — perfect result!
Finish with the LED and Sensor Holes

Step 4a: Use the blunt end of a 7/32" drill bit centered on the pilot hole to mark the LED and Sensor Holes.

Step 4b: Holes are marked.

Step 4c: 1/16" pilot holes done.

Steps 5 & 6a: Pilot holes are enlarged for the LED and Sensor Holes. If you do not have an 11/64" bit for the Sensor hole, work a 5/32" bit to enlarge to 11/64".

Steps 5 & 6b: Smaller LED Hole above the larger Sensor Hole in this view from below.

Step 7: All done and ready for action!