1. Switch Machine Wiring and Adjustment Tests
Switch machine wiring and adjustment tests verify the wiring and adjustment of the switch machine. These tests should preferably be carried out, in conjunction with the track installer, to confirm throw rod capability, ensure point closure, and ensure proper nesting of the switch point rail to stock rail.
2. Switch Machine Appurtenance Test
Switch machine appurtenance tests verify the integrity of switch machine layout by taking resistance measurements across the following assemblies:
- Center insulation of the front rod
- Front rod to switch point
- No. 1 vertical or horizontal switch rod center insulation
- Throw rod insulated from No. 1 switch rod
- Point detector piece insulated from switch point
- Lock rod insulated from front rod
- Other vertical rods as required per layout
- Switch machine insulated from the running rails
- Switch machine extension plate insulated from the running rails
3. Insulated Joint Test
Insulated joint tests measure the resistance between two ends of the rail separated by insulating material. An insulated joint checker requires the traction power system to be disconnected. Any reading less than 30 ohms should be evaluated. Measurements for a set of insulated joints should be within 30% of each other or they should be rechecked. Insulated rail joint tests for AC track circuits can be performed using a volt-ohm-meter.
4. Impedance Bonding Resistance Test
Impedance bonding resistance tests, using a low-resistance ohm-meter, ensure that a proper connection has been made.
5. Power and Signal Bonding Test
The power and signal bonding test is to ensure that the resistance across the rail connection
6. Negative Return Bonding Test
Negative return bonding tests verify the resistance of each mechanical or welded power bond using a low-resistance ohm-meter.
