SECTION 15 – MATERIALS AND WORKMANSHIP
North American transit equipment experience indicates that construction must be to a high standard to achieve satisfactory vehicle service under the environmental and operating conditions which prevail. Specific standards with respect to material and workmanship are necessary. This section defines the minimum performance requirements for materials to be used in the construction of the streetcars and establishes minimum guidelines for workmanship. It identifies mandatory government requirements and industry specifications controlling the quality of specific materials and components and the construction methods. Alternatives will be considered.
The Contractor shall ensure that all equipment, materials, manufacturing, assembly, and installation processes and practices are in full conformance with the intent and the requirements of this Specification as well as with proven and recognized industry practices and recommendations.
All materials shall conform to the appropriate industry standards for use on rail transit equipment. These standards include Federal or Military Specifications or Standards, the Specifications of the Aluminum Association of America, AAR, ANSI, ASME, ASTM, FRA, IEEE, IEC, EN, or other requirements as specified herein. Foreign or international standards are encouraged to be proposed by the Contractor as alternatives. The Contractor shall submit proposed standards in English for review by the City. A service history of equipment built to these standards may be included to demonstrate the applicability of the standard.
15.1.3 STORAGE OF MATERIAL
All equipment and material intended for use in these cars shall be shipped and stored such that damage or reduction in life is prevented. All stored material subject to corrosion shall be protected by waterproof covers or coatings. Materials and equipment shall be stored under cover and off the floor or ground.
All equipment shall be stored with all ports, covers, and all other enclosure openings closed to prevent ingestion of dirt or moisture.
All dated material shall be clearly marked with the expiration date and shall not be used beyond the expiration date. All material with special handling or storage requirements shall be handled or stored according to the manufacturers requirements.
All material shall be clearly marked and/or stored with appropriate nomenclature to prevent misapplication.
Rejected material shall be clearly marked as such and stored in an area specifically designated for that purpose.
15.1.4 PROHIBITED MATERIALS
The following materials are prohibited for use in the construction of these cars, except where specifically permitted:
; Lead in brake shoes
; Urethane Foam
; Aluminum Threaded Fasteners
15.1.5 DISSIMILAR MATERIALS
In this context, dissimilar materials refers to materials that corrode or otherwise become damaged when in contact with other materials.
Connection of dissimilar materials is permitted only at permanent connections and with suitable electrochemical isolation. All such isolation treatments shall be permanent and not require maintenance or replacement for the life of the car.
Dissimilar materials are not permitted at electrical connections or connections requiring disassembly for maintenance or for removal and replacement of equipment.
15.2 JOINING AND FASTENING
All bolts, screws, nuts, washers, and other related fastening devices shall be plated steel, stainless steel, or aluminum. All threaded, 1/4-turn, or otherwise non-permanent fasteners shall have Phillips, tamper proof, hex socket, or hex heads. Slotted-head fasteners shall not be used unless specifically approved by the City for application inside equipment enclosures and for bolts 5 mm diameter or less.
Except for fasteners internal to electrical or electronic components, plastic screws, bolts, nuts, or other plastic fastening components shall not be used unless approved.
Protruding screws, mounting bolts or similar items will not be permitted either on the interior or exterior of the car, except for those appointments which can not be built into the structure in any other manner. Interior or exterior screws, bolts, and nuts exposed to passengers shall be used only if approved.
All fasteners used for access panels, equipment box covers, or other areas requiring frequent operator or maintenance access shall be captive to the cover.
Fasteners shall not be used near heat sources that will exceed the fastener manufacturer's recommended operating temperature or otherwise damage or reduce the life of the fastener.
18.104.22.168 THREADED FASTENERS
Threaded fasteners shall have screw thread conforming to ISO-metric standards. Metric fasteners shall be identified as required by applicable ASTM specifications, abstracted in "Metric Fastener Standards", Industrial Fasteners Institute, latest edition.
Self-tapping screws shall not be used except as approved for a specific application. All fastenings on access panels, plates, covers, of other components accessible by passengers, shall be a tamper-resistant type.
Stainless steel screws or bolts, nuts, flat washers, and lock washers shall be used in mounting, and in making connections at power resistors and other heat-producing apparatus where copper, stainless steel or other high expansion alloys are connected. For carbon steel or other low expansion materials that produce heat, connections shall be made with Grade 5 zinc plated hardware. Cadmium plated fasteners shall not be used to connect heat producing devices.
All structural or load carrying bolts shall be a minimum of Grade 5 and the bolt diameter shall be no less than M10, regardless of design load. Stronger fasteners shall be used if the application requires.
When bolts are used to secure apparatus where the bolt head is inaccessible, a reusable mechanical locking device shall be used to prevent the bolt head from turning when the nut is being removed.
At least 1a screw threads shall project beyond all nuts.
22.214.171.124 WASHERS AND LOCK WASHERS
Washers shall conform to ANSI B18.22M, latest revision, as is appropriate for the application.
Flat washers shall be used on both sides of all electrical connections, that is, under the bolt head and the nut.
Lock washers shall not be used in structural applications or in fatigue applications where the fastener must be torqued and marked. All lock washers shall conform to International Fastener Institute (IFI) 1970 Fastener Standards.
Predominant type nuts shall be regular-height, nylon-insert, self-locking ESNA stop nuts or approved equal. Self-locking nuts shall be used throughout, where practical. Non-self-locking nuts with lock washers may be used in non-structural applications upon approval by the City or where required by the Specification.
Nylon insert lock nuts shall not be used near heat sources that will exceed the manufacturers recommended operating temperature.
All threaded fasteners shall be torqued to a value assigned by the designer or to standard torque values recommended by the fastener manufacture. All safety related fasteners, including truck and brake equipment bolts, shall be "torque-striped" after torquing by paint or equal approved means. 15.2.16 RIVETS
Rivets and lock pins exposed to passengers shall be stainless steel or aluminum as appropriate to the materials being joined.
15.2.2 JOINT FITTING
Joints shall be properly fitted, whether exposed or concealed. Gaps between joints shall be held to a minimum and be uniform in width. The edges of panels shall have a smooth, finished appearance. 15.2.3 METAL-TO-METAL CONNECTIONS
Where metal is riveted or bolted to metal, contact surfaces shall be free of dirt, grease, rust and scale, and shall be coated with a metal base primer.
If aluminum parts are used for any purpose, metal-to-metal connections shall be in accordance with the latest revision of "Specifications Covering Use of Aluminum in Passenger Carrying Rail Vehicles"; Technical Report Number 524 by the Aluminum Company of America.
15.2.4 WOOD-TO-METAL CONNECTIONS
Where wood and ferrous metal surfaces are placed together, the wood shall be coated with aluminum paint conforming to Federal Specification TT-P-38, and the metal, shall be coated with a primer which conforms to Federal Specification TT-P-664
All bolts or rods passing through wood shall be coated with aluminum paint conforming to Federal Specification TT-P-38.
If aluminum parts are used for any purpose, wood-to-metal connections shall be in accordance with the latest revision of "Specifications Covering Use of Aluminum in Passenger Carrying Railway Vehicles" per Technical Report Number 524 by the Aluminum Association of America.
15.2.5 WOOD-TO-WOOD CONNECTIONS
Where wood and wood are placed together, both abutting surfaces shall be coated with aluminum paint conforming to Federal Specification TT-P-38.
15.3 STAINLESS STEEL
Structural stainless steel components shall be of AISI type 201L or 301LN and shall conform to the requirements of ASTM A 666 except that the carbon content shall not exceed 0.03 percent and type 301LN may contain up to 0.25 percent nitrogen. Other high strength stainless steels proposed by the Contractor may be used if approved by the City.
Stainless steel used in non-structural applications shall be AISI types 201, 202, 301, 302, 304, 316, 430 or as proposed by the Contractor and approved by the City.
15.4 LOW-ALLOY, HIGH-TENSILE STEEL
Structural shapes, plates and bars shall conform, as a minimum, to the requirements of ASTM A 588. General requirements for delivery of LAHT shapes, plates, and bars shall be as required by ASTM A 6.
Welded LAHT steel shall develop 20 foot-lbs Charpy V Notch impact strength in the CGHAZ (Coarse grain heat affected zone 1mm from fusion area) at 0EF.
Hot rolled or formed structural shapes may be used for non-structural applications including equipment supports, jack pads, and clip angles.
Cold and hot rolled LAHT sheet and strip shall, as a minimum, conform to the requirements of ASTM A 606, Type 4. General requirements for delivery of these products shall be as required by ASTM A 568.
Other low-alloy, high-tensile steels which meet or exceed the above requirements may be used, provided their detailed specifications are submitted and approved as equivalent, or better material, for the proposed applications.
All LAHT steels shall be applied according to their specification properties.
15.5 STEEL CASTINGS
Steel castings used in any location throughout the car shall be selected by the Contractor for composition, heat treatment, and design best suited for the intended service.
All steel castings shall be sound throughout and shall be suitably marked with pattern and serial numbers in a manner that will not impair their strength.
All steel castings used in the truck structure, bolster, and center bearing arrangement shall meet AAR Specification M-201 latest revision, Grade "B", plus 2% nickel, minimum. These castings shall be heat
treated to develop a minimum tensile strength of 517 MPa, a minimum yield strength of 331 MPa,
elongation of not less than 25% in 50.4 mm, and reduction of area of not less than 50%.
Magnetic particle inspections of all surfaces of all castings shall be conducted in accordance with ASTM E 709, by personnel certified to MIL-STD-410A, latest revision.
Where specified or required, radiographic inspection meeting the requirements of ASTM Standard E 94 and using reference radiographs to ASTM E 446 shall be applied.
Welding of castings is permitted, provided the casting supplier performs all repair welds in accordance with an approved written procedure and uses welders qualified to ASTM A 488.
Aluminum alloy mill products shall be identified by designations prescribed by the Aluminum Association of America and shall conform to specifications contained in the Association's publication "Aluminum Standards and Data". Castings shall conform to ASTM B 26, B 85, and B 108 for sand, die, or permanent mold castings respectively. Aluminum alloy forgings shall conform to ASTM B 247.
Protection shall be provided at the contact surface of all connections to aluminum. The following instructions are provided for general guidance and shall not be construed to supersede conflicting recommendations by the aluminum manufacturer or by the Aluminum Association of America Technical Report No. 524.
The contact surfaces of aluminum alloy with aluminum alloy shall be etched or anodized before securing. Aluminum alloy surfaces shall not be secured to, nor make direct metal to metal contact with the surfaces of copper, copper bearing aluminum alloy, brass, bronze, silver, nickel and nickel plated parts or alloys thereof, lead, tin, ferrous materials and wood.
The surfaces of aluminum alloy parts secured to steel parts shall be protected as follows:
; With a one-part polysulphide sealant or zinc chromate paste.
; Alternatively, an approved insulation joint material, which completely covers the fayed surfaces,
may be used. The material shall be non-hygroscopic and, if fibrous, shall be impregnated with
bitumen or some other approved water and moisture-repellant substance. Fasteners shall be
primed and painted with red oxide or aluminum paint after installation.
Wood-to-metal connections shall be as specified above. The wood shall be thoroughly dried and then coated with varnish or other comparable sealant, as approved.
Carbon steel fasteners shall be cadmium plated as required above. The entire fastening, including washers and nuts, shall be plated and where possible, the head and unthreaded portion of the shank of the bolt shall be in contact with the aluminum part when secured in place. Suitable bushings may be used.
Rivets driven hot may be considered as covered by a protective oxide coating due to the heating, but the method of riveting shall, if possible, always be with the formed rivet head in contact with the aluminum alloy.
15.7 WELDING AND BRAZING
The Contractor shall control the quality of all welding and brazing, including that of its subcontractors. Prior to performing work under this Contract, all welders shall have been tested to confirm their ability to operate the welding equipment and to make the types of welds required by the design or this document.
15.7.1 STRUCTURAL WELDING
All structural welding practices not specifically covered in other sections of this Specification shall be in accordance with requirements of EN287-1 for steel; EN287-2 for aluminum;; and the AWS Handbook. Resistance welding shall be in accordance with MIL-W-6858. Requirements for dynamically loaded structures shall have precedence over those for statically loaded structures.
Structural welding of stainless steel by the fusion-arc process shall be governed by ASME Section IX and ASME Section VIII, Part UHA. AISI 201L and 301LN stainless steels shall be treated as P-No. 8, Group-No. 3 category for reference to ASME requirements. Weld heat affected-zones (HAZ) and weld metal shall be limited to maximum allowable stress values in ASME Section VIII, Table UHA-23 for UNS S20100 stainless steel and Table UW-12 rating of