AEI Site Installation Procedure

Railnet AEI System Site Installation Manual
This chapter explains how to prepare and install an AEI site. If your site installation involves a procedure not included here, refer to section 1.3, Additional Information.= Site Preparation =

Site Considerations

Pre-construction

1. Find the transducer location first. This is the center of the site. The center of the transducer must be located between two ties. This allows the cable at the bottom of the transducer to enter the Carflex conduit without binding.
2. Find the tower locations. Since the center of the antennas and the center of the transducer must line up, the towers will be offset from the transducer. (The antennas mount to the side of the tower.)

Areas to Avoid

Comet Electronics recommends that the following site areas are avoided. Use this list as a guide only. Since all installations are unique in some manner, avoiding these areas is not always possible. A survey of each site should be done to determine preferred equipment locations, conduit runs, and antenna configuration based upon the particular application. The user and the system integrator must ensure correct and accurate system operation in the event the areas described below cannot be avoided.

• Large metallic objects and obstructions in close proximity to the reading area
• Areas where reverse train movements occur
• Areas where train switching moves occur
• Areas where “building” moves occur (dropping and adding cars)
• Areas where train stoppage in front of reader systems is likely to occur
• Areas with severe or multiple curves in the track
• Switches
• Track joints
  

Construction

1. Install house foundation legs at top of tie level. All trenching is to be 36" below top of tie.
2. Set tower foundations.
3. Install all conduits in the same trench. Conduit runs on drawings are guidelines. They may be changed to fit site specific requirements. Use sweeps-not elbows!
4. Install tower sections and tower caps.
5. Install low antenna mounts (if required).
6. Install tower junction box and splice pedestal (if used) as needed. Location of pedestal is a suggestion; it may be moved to fit site specific requirements.
7. Install Carflex conduit from pedestal (if used) or junction box to transducer location.
8. Install loop cable on track.
9. Loop cable must be twisted 5 times per foot from track to pedestal (if used) or junction box. Install twisted loop cable in Carflex conduit.
10. Install ground rods and cabling. (Pigtail at corner ground rods into hut).
11. Attach ground wire to low mount with a ground lug (if low mount required).
12. Use the CADWELD exothermic welding system for ground cable to grounding rod connections.
13. Tamp all excavations and trenches.
14. Restore ballast to pre-dig condition. Supply fresh ballast where required.
15. Tape all ends of exposed conduits or Carflex conduit to prevent water, rocks, or other debris from entering.
16. Clean up site area.

Single and Double Track Sites

Single Track Site Installation

1. Set instrument house, securing all four corners.
2. Connect ground wire pigtails to ground panel.
3. Seal cable entry holes with Ductseal.
4. Mount parapanel antennas with check tags.
5. Install Sealtite assembly and 4' coax jumpers to parapanel antennas.
6. Insert check tag cable into Sealtite assembly to tower junction box.
7. Pull in 1/2" Heliax and 4c 22 gauge check tag cable from near side tower junction box to bungalow. (3” conduit)
8. Pull in 1pr 16 gauge loop lead-in and 2pr 18 gauge transducer cables from junction box or splice pedestal (if used-otherwise install in 3" with heliax) to building. (2” conduit)
9. Mount antennas without check tags to remaining locations.
10. Pull in 1/2" Heliax cable from far side antenna box.
11. Splice, waterproof, and terminate all cables.
12. Install the Tiefenbach transducer. Refer to Section 2.3.1 Tiefenbach Installation for installation instructions.

Double Track Site Installation (Restricted)

1. Set instrument house, securing all four corners.
2. Connect ground wire pigtails to ground panel.
3. Seal cable entry holes with Ductseal.
4. Mount parapanel antennas with check tags to towers on all sites. The near track gets the antenna with a check tag. The check tag is mounted on the antenna that is on the bungalow side of the tracks. On double tracks, the far track also gets an antenna with a check tag. It is mounted on the antenna farthest from the bungalow.
5. Install Sealtite assembly and 4' coax jumpers to parapanel antennas.
6. Insert check tag cable into Sealtite assembly to antenna junction box.
7. Pull in 1/2" Heliax cable and 4c 22 gauge check tag cable from each tower junction box. (3" conduit)
8. Pull in 1pr 16 gauge loop lead-in and 2pr 18 gauge transducer cables from far side junction box or splice pedestal (if used-otherwise install in 3" with heliax) to building.
9. Mount log periodic antenna. (if required by site configuration)
10. Pull in 1/2" Heliax cable from each log periodic antenna. (3” conduit). (if required by site configuration) Optionally, wheel detector and loop termination may be in log periodic enclosure for antenna 0 of far track. Install accordingly.
11. Splice, waterproof, and terminate all cables.
12. Install the Tiefenbach transducer. Refer to Section 2.3.1 Tiefenbach Installation for installation instructions.