Download American Audio VELOCITY - REV 4-05 Operating instructions

METRO RAIL DESIGN CRITERIA
SECTION 9 / SYSTEMS
by a yellow warning tape 6 inches wide marked "Warning - High Voltage",
laid 12 inches above concrete encasement in backfill.
14. Feeder ductwork shall be run as directly as practicable and shall be located
to avoid interference with foundations, piping and other similar underground
work. Risers consisting of PVC coated galvanized rigid steel conduit shall
be provided at feeder connections to the wayside distribution.
B. Contact Rail
1. The contact rail shall be bi-metallic. The two metal components of contact
rail shall be forced to make permanent contact by applied pressures from
bolts or equivalent methods, and interfacing surfaces shall be well cleaned
to minimize electrical resistance between the metals. Contact surfaces shall
be tightly sealed to prevent ingress of polluting or corroding matter.
The contact rail for the main line shall have an electrical resistance not
greater than 0.002 ohms per thousand feet at 20˚C, and shall be capable of
carrying 4,000 amperes DC continuously at a temperature rise not
exceeding 40˚C over a 30˚C ambient in still air.
The contact rail for the yard area shall have an electrical resistance not
greater than 0.004 ohms per thousand feet at 20˚C, and shall be capable of
carrying 2,000 amperes DC continuously at a temperature rise not
exceeding 40˚C over a 30˚C ambient in still air.
2. Contact rail height shall allow sliding of current collector shoes on top of
contact rail when the contact rail is seated upon support. The top wearing
surface of the contact rail shall be at least 2 inches wide to lessen wear.
3. The support insulator shall be centered below contact rail and the insulator
base shall be sufficiently wide to provide a stable arrangement for the rail.
The contact rail and support insulator shall withstand without permanent
deformation the stresses caused by the maximum short circuit forces.
4. Contact rail joints shall not have misalignment or roughness. Bolted butt
joints shall be ground smooth for minimum wear and abrasion of collector
shoes.
5. Feeder connections to contact rail shall be suitably designed, located, and
attached to provide permanent connection without excessive protrusion from
the side of the rail.
6. The standard rail lengths shall be interconnected by means of bolted or
welded joints.
7. The relative position of the contact rail to the running rails shall be
coordinated with the design of the vehicle current collector.
8. The standard contact rail lengths shall not be less than 39 feet nor more
than 60 feet plus or minus one percent. The rail shall have sufficient section
modulus so that the maximum sag with a concentrated load of 30 pounds at
DE304.09
Metro Baseline
9-147
Revision 4 : 05/09/12
Re-Baseline: 04/29/10