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Chassis
Assembly Specifications
1.
Chassis Frame Assembly
(a) The chassis frame shall be constructed of
110,000 psi minimum yield strength steel.
(b) The chassis frame
assembly shall be treated with epoxy chromate primer and painted
with black enamel paint.
2. Air System
(a) The trolley air system shall
be capable of operating all accessories, the braking system, and
the suspension system, with an adequate reserve capacity. The
engine driven air compressor shall be sized to charge the air
system from forty (40) psi to governor cut off pressure in less
than four minutes while not exceeding the engine's fast idle
speed. The compressor shall be a Bendix Two Flow.
(b) The air system shall consist of at least
three (3) cylindrical air reservoirs with at least four (4)
compartments located between the chassis rails with a combined
minimum capacity of 4,100 cu. in. All reservoirs shall be
equipped with drain valves.
(c) A B/W AD 9 desiccant type air dryer shall be
provided to prevent the accumulation of moisture in the air
system. The air dryer shall be vertically mounted with an easily
replaceable desiccant cartridge and a thermostatically
controlled heater element.
(d) The air system shall be supplied from the
third protected air reservoir equipped with a low pressure
protection valve set at 65 PSI.
(e) The Bendix D2 air governor shall be equipped
with a (Schraeder type) valve for shop service and shall be
located for ease of adjustment or replacement.
(f) Air lines shall be nylon tubing and routed
for maximum protection and serviceability. All component
fittings shall be installed for maximum serviceability from the
underneath side.
(g) All air system components shall be easily
accessible.
3.
Suspension
(a) The suspension both front and rear shall be full air
spring type using rolling lobe air springs. Spring rate shall be
75 to 80 cycles per minute.
(b) The front suspension shall utilize one (1) leveling
valve.
(c) The rear suspension shall utilize air springs with two
(2) leveling valves. Lateral movement shall be controlled on
both front and rear axles by rubber bushed radius rods.
Torsional and lateral movement is controlled on the rear
suspension with a high capacity torsion bar.
(d) Both front and rear suspensions shall be equipped with
heavy-duty double-acting hydraulic shock absorbers properly
valved for air springs.
(e) This suspension shall be assembled to the chassis
supported with cross members at all frame connections.
(f) Front suspension shall be equipped with a bus kneeling
feature.
4.
Axels
(a) Both the front and rear axles must be of an approved
American manufacture, designed for transit application.
(b) The front axle shall be a reserve Elliott type, I-beam
center, with a capacity of 11,000 lbs. This axle shall provide
maximum maneuverability with an 79.5" track.
(c) The rear axle shall be a heavy-duty full floating type with
a capacity of 19,200 lbs. The ring and pinion gear ratio is to
provide approximate coach speed of 56 mph. The rear axle is to be
equipped with a hex head magnetic drain plug.
5.
Brakes
(a) Brakes both front and rear shall be adequate for the
proposed GVW with automatic slack adjusters and S Cam actuated.
(b) The brake lining material shall be Non-Asbestos.
(c) The vehicle shall be equipped with a parking brake.
(d) The rear brake system shall be interlocked with the doors
so that the coach has to be brought to a complete stop when the
doors open and then locks the brake application while the doors
remain in the open position. This brake system shall meet
standard FMVSS-121 as applicable.
(e) Warning devices to indicate low air on the primary and
secondary air systems shall be installed.
6.
Wheels And Tires
(a) Wheels shall be spoked disc ventilated type. Size 22.5 x
7.50 wheels shall be stud mounted and retained with ten (10)
studs on an 11-1/4" bolt circle.
(b) Tires shall be Goodyear 245/75R x 22.5, single front and
dual rear. Tires to be furnished by coach manufacturer.
(c) All tires and wheels shall be interchangeable, front to
rear.
(d) One spare wheel and tire will be supplied with each
vehicle.
7.
Steering System
(a) Shall be hydraulic powered integral steering gear to
provide ease of steering and full maneuverability at vehicle
loads. Reservoir shall be serviceable from outside of the coach.
(b) Steering column shall be equipped with 18" x 1"
grip steering wheel, with integral center horn button. The
steering wheel angle shall be adjustable by the driver and the
column shall telescope.
8. Engine
(a) Shall be a Cummins 5.9 liter heavy duty diesel engine or
approved equal.
(b) Engine shall deliver minimum rated power of 230 brake
horsepower at 2500 RPM and 605 foot pounds of torque at 1600
RPM.
(c) Engine shall be equipped with an automatic engine
shutdown and alarm.
(d) The engine is to be mounted on a four-point mount using
rubber isolator mounts to provide maximum vibration isolation
and dampening. Engine shall be cradle mounted.
(e) Engine shall comply with all Federal and State laws and
regulations with regard to air and noise pollution that are in
effect on the date of manufacture.
(f) The engine and components are to be arranged and mounted
so as to provide convenient access for servicing the engine and
all of its accessories from outside of the vehicle. Mounting of
engine shall provide for engine removal from outside the
vehicle.
9.
Engine Oiling System
(a) The engine shall be equipped with a full flow spin on oil
filter which is to be incorporated with a plate type oil cooler
and an internal by-pass valve which assures oil flow.
(b) The engine oil pan shall be equipped with a hex head
magnetic drain plug. (c) Oil filler tube and dip stick shall be
easily accessible from outside of the vehicle.
10.
Fuel System
(a) Fuel tank shall be a minimum 100 gallon
capacity internally baffled, mounted between the frame rails of
the coach. Plastic tank is not acceptable.
(b) This tank shall have a 20 gallon per minute
fill pipe, audible fill signal, and 1/4 turn brass drain valve.
(c) This system shall incorporate one (1)
spin-on five micron fuel filter and a fuel water separator.
(d) The supply and return fuel lines shall be
steel tubing, and flexible fuel lines in the engine compartment
shall be Teflon core stainless steel jacketed hose.
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