MONONGAHELA INCLINE PLANE HAER No. PA-226 Connecting the North Side of Grandview Avenue at Wyoming Street with West Carson Stree
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MONONGAHELA INCLINE PLANE HAER No. PA-226 Connecting the north side of Grandview Avenue at Wyoming Street with West Carson Street * - * near Smithfield Street fV/f rr.V-1. Pittsburgh ... A Allegheny County f -B7 Pennsylvania f\ t\,-- - '<./■; > ifUw.^ PHOTOGRAPHS WRITTEN HISTORICAL AND DESCRIPTIVE DATA HISTORIC AMERICAN ENGINEERING RECORD National Park Service Northeast Region U.S. Custom House 200 Chestnut Street Philadelphia, PA 19106 HISTORIC AtlERICAN ENGINEERING RECORD a-PiTBO nONONGAHELA INCLINE PLANE HAER No. PA-226 LOCATION: flonongahela Incline Plane* connecting the north side of Grandvieu Avenue at Wyoming Street with the south side of Ulest Carson Street near Smithfield Street, Pittsburgh, Allegheny County, Pennsylvania DATE OF CONSTRUCTION 1870, passenger incline plane; 1382, freight incline plane ENGINEER: John J. Endres PRESENT OWNER: Port Authority of Allegheny County Beaver and Island Avenues Pittsburgh, PA 15233 PRESENT OCCUPANT: Port Authority of Allegheny County Beaver and Island Avenues Pittsburgh, PA 15233 PRESENT USE: Passenger transportation between West Carson Street near Srnithfield Street and Grandview Avenue, Mount Washington SIGNIFICANCE: The first constructed and oldest passenger incline plane in Pittsburgh, this system retains the 1882 safety brake and bull wheel and 1935 electrical system including drive motors, operating brakes and power cable system. PROJECT INFORMATION: The do cumentat io n of the Monongahela Inclin e Plane wa s un derta ken in January- June, 1993, to m i t ig ate t he adverse effect of pla nned chang es t o the transportat ion system This do cume ntat i on was stipulated by the State His tori c Pr& servat ion Officer as par t of a Mem oran durn o f Agreement. Docume ntation ha s be en pr epared by Rebecca n. Rog ers, Histo r ic Prese rvat ion Consul tant, 44 A udub on Ro ad, Youngstown, Ohio 44514. Th e pr oject team included: Rebecc a M. Roger s( a rchi t ectural historian, and Da vid Thum, phot ograp her. M0N0N8AHELA INCLINE PLANE HAER No. PA-226 (page 2) The Monongahela Incline Plane is a transportation system nou owned by the Port Authority of Allegheny County. It connects Carson Street, near the Smithfield Street Bridge, on the south side of the flonongahela River with Grandview Avenue on the northern edge of Mount Uashington in Pittsburgh, Pennsylvania. This incline plane consists of two parallel steel rail tracks on the Mount Uashington escarpment that carry two cars up and down the hillside between an upper station (1882) and a lower station (1904). The incline plane system runs approximately north and south, with the louer station on the north end and the upper station on the south end. The road bed is 365* 1ong. An electric elevator-type motor system powers the incline plane (1935) . The cars are pulled by steel ca bl es . A secondary cab! e and brake system insure safety (1882). This uas the first pas- senger incline plane constructed in Pittsburgh and is one of five passenger incline planes still operating in the United States. A passenger incline plane is a large example of the simple machine as defined in physics, used for transportation of goods or persons. For this unusual transportation system, a hillside is the wedge or angle of the mechanical tool* The "pull" comes from an engine or motor and the counterweight of a car running on a parallel track down the hillside. A steel cable acts as the rope connecting the up and the down cars. The p re sent Mono ngahe1 a i ncl ine pl an e system cons is ts of the two cars, t he tr ack and the cabl e de pend ent on a motor drive svst em desig ne d and man ufact ure d by Oti s El evat or Co mpany in 1935. The svste m moves the cars by the fri ct io n of the cable' s contact with tuo d ri ve wh ee 1 s driven by t wo e lect ric motor s. Th e ent ire d rive syste m is ho used in the base ment of the upper stati on. The s teel cab 1 e i s att ache d to the uph ill end of the bo t torn o f each car and passe s from each car int o th e mo tor room belo w the upper stat ion wai t i ng room f lo or. The ste el d rive cable an d safe ty cables are 1-1/4 diame ter st randed ste el o ver an indepe ndent wire rope core. The c able from ea ch c ar m oves on a cas t st ee 1 "deflect or sheav e" 7' i n di ameter. A d efle ctor sheave i s simi lar to a pull e y wheel wit h tuo gr oove s * The i nsi de gr oove c arries the drive c abl e and the out s ide groo ve c arri es th e safe ty cable. Two addit io nal 7 ' in diamet e r de flee tor sheaves a re rnou nted at a si i gh t ang 1 e , ne ar1y ver t ica 1 , i n d i rect 1ine wit h each of th e two i nc I ine pi an e tracks . E ach is m ounted ab ove on e of the motor s in th e mo tor room . E ach of t hese defl ector sheaves dir ec ts the dr iv e cab 1 e too ne o f tw o drive s heaves mounted vert i ca II y • be 1 o w, and n ear 1 y 90 deg rees cros swise to the def le ct or sh eave s. in a Pit at t he f ar south side o f the moto r room. The h ub o f each d r ive she ave is connec ted di rect1y to a her r i ng bone dr iv e gear. The her ring bone d r i v e gear is driven by a her r i ngbon e pi n i o n g e a r wh ich i s i n di rect 1 ine w ith a spri ng 1 oade brake and 250 vo It, di re ct c urrent mo tor, s hunt wound The 7 diame ter cast ste el d rive she aves have spi ra 1 grooves MONONGAHELA INCLINE PLANE HAER No. PA-226 (page 3) all owing two wraps of the cable, moving it by the friction of double wrap of cable on the grooves. The pouer is supplied from public service entry on the southeast corner of the upper station. Pouer to the system is furnished through a 75 motor-generator running at 1200 revolutions per minute* supplying 240 volts of direct current to the motors. The drive system is basically the same as an elevator drive system. The motors are mounted in line with the steel cable connected to the incline plane cars just beyond and slightly belou the end of the incline plane track. Speed is increased or decreased according to the voltage applied to the motor. Uhen the power is cut, the cars stop. Between each motor and its drive wheel is the brake. Braking is accomplished by cutting the power to the motor through a spring loaded arm* Above and between the motors is a governor switch that controls the drive speed, engaging the brake if the motor exceeds an accept able limit. The safety braking system for the incline plane was designed by Samuel Diescher and installed in 1882 beneath the upper end of the incline plane track just outside the upper station. It is protected from the weather by the roof overhang. This system consists of a cable attached to each car, a 10* diameter cast iron wheel, and an air brake. The brake wheel or "bull wheel" is supported by an iron truss which is hung from the main center rail truss by three steel plates. The south end of the center rail truss is supported by a 28" steel I-beam supported between the two projecting bays of the upper station. The bull wheel truss is supported on a stone and concrete foundation on the north and hung from the 28" steel I-beam and the center rail truss on the south. The 15" deep bull wheel truss is made of paral1 el iron 7-1/2" "C-shaped" channels, with two upper chord channels and two 1ower chord channels. The bull wheel sits parallel to the plane of the track between the top and lower chord of the truss. The bull wheel is cast in two hemispheres which are bolted together. The entire wheel has six spokes that support a 10" wide outer rim with a 4" upper groove for the safety cable and a 4" lower channel for the steel brake band with brake shoe lining. The safety cable is attached to the bottom of each car, like the drive cable. It passes from the car to the outer groove of the deflective sheave, then to the upper groove of the bull wheel , across the second deflective sheave and to the other car. The safety brake is activated by an air cylinder with a piston 12" diameter and 15-1/2" long. The control for the safety brake is in the operator's cabin which is called a "pulpit". Air lines run from the pulpit to the air cylinder.