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Home , Pendolino, Tilting train

Tilting shorten transit time Old, curved tracks typically throw high-speed rail travel­ Downloaded from http://asmedigitalcollection.asme.org/memagazineselect/article-pdf/120/06/78/6381581/me-1998-jun6.pdf by guest on 26 September 2021 and travelers-for a loop. Tilting trains can keep the speeds up without causing passenger discomfort. By Michael Valenti, Associate Editor

IGH-SPEED RAIL IS fast becoming a popular mode ing them into their seats. The lateral acceleration can be­ of travel in Europe and more recently in North come very uncomfortable for riders, making them feel H America, with countries planning new systems like they're in an amusement-park ride; in the cafe cars, every year. Although national governments may be ready for example, diners will spill food and drink because of for trains speeding along at 250 kilorneters per hour or the forces occurring in the curves. To avoid this problem, more, the regional geography is not. Tracks often must trains must slow down, but this negates high-speed rail's snake through mountainous terrain and other obstacles, greatest benefit and makes for longer journeys. which can create problems at high speeds. The seemingly simple solution would be to build straight When trains head into these curve at high speed, pas­ railway tracks. 's Train a Grande Vitesse and sengers inside can feel gravity and centrifugal force press- Germany's high-speed systems have adopted this strategy of new lines dedicated to high-speed trains. This concept works best if the builder has a lot of open space, which has become a rare commodity not only in some parts of the United States but in a rapidly develop­ ing Europe as well. Such right­ of-way construction also in­ curs high capital costs, takes a great deal of time, and has a variety of potentially harmful impacts on the environment. • Another option is to design --- trains that will tilt when ne­ gotiating curves on existing tracks so as to reduce cen­ trifugal force on passengers

This Fiat train negotiates curves at high speeds through the timeless Italian countryside by virtue of actuators that tilt its cars, reducing the centrifugal force on passengers. yet maintain fast speeds on the ride. Two recent major at up to full speed, which is 35 to 45 percent faster than rail projects have chosen this approach. London-based conventional trains without any effect on the quality of Virgin Rail has signed one of the largest international the ride. railroad contracts ever for a fleet of tilting trains from Fiat A key feature of the Pendolino's system is its active lateral Ferroviaria S.p.A. in Savigliano, , to run on Great suspension. This particular device is fed by the signals Britain's high-speed . Half a world coming from the accelerometers and compensates lateral away, a line in the Pacific Northwest will use tilting trains accelerations due to irregularities instantaneously, from Patentes S.A. in Madrid, , to move at increasing running comfort. up to 125 kilometers per hour-not exactly a high speed The trains derive their performance from their mod­ but still one that can reduce travel times significantly. ular bogie, control and auxiliary systems, suspensions, and lightweight double-skin cars made of extruded THE LITTlE PENDULUM aluminum (requiring only longitudinal welds). The Downloaded from http://asmedigitalcollection.asme.org/memagazineselect/article-pdf/120/06/78/6381581/me-1998-jun6.pdf by guest on 26 September 2021 Engineers at Fiat designed their first tilting passenger trains tilting system is mounted under the car's body to nearly three decades ago. The trains are called Pendolino, preserve the space in the vestibules and passenger com- or "little pendulum;' because partments. Both the primary they automatically tilt the and secondary suspension of passenger cars by means of the bogie are helical to hydraulic or electromechani­ ensure protection against cal tilt actuators-depending derailment. on operational require­ The bogie frame, suspen­ ments-connected to the sions, and axles of the carry­ wheel assemblies, or bogies, ing and motor bogies are in­ when negotiating curves at terchangeable; the sole any speed. This system always exception is the motor or positions the coaches in their driving axle in the motor bo­ optimal position. gie, on which the final drive "Only minimal modifica­ is mounted. The traction tion of existing train tracks is motors of the Pendolino are required to accommodate located under the body and the Pendolino," said Andrea Fiat engineers house the hydraulic or electromechanical actuators of the connected to the reducer by Pendolino trains in the bogies completely under the cars to preserve M azzotto, an econonllst and space in the pa ss enger compartments. a cardan shaft, which trans­ manager of export sales at nuts power from the motor Fiat. These changes mean ramping the outer rail pro­ to the motor axle, to reduce the unsprung masses. gressively higher so the Pendolino's instruments can The Pendolino uses four-quadrant, converterlinverter sense a curve better, and installing a signaling system that traction equipment powered by a catenary 25-kilovolt, 50- will alert drivers when they are moving faster than the . hertz voltage that is supplied by eight three-phase, 500- top speed of 250 kilometers per hour. Even with these kilowatt ac motors. Thyristors made by another Fiat sub­ nlinor changes, the cost of using tilting trains for fast rail sidiary, Parizzi S.p.A. in , Italy, supply the optimum travel on existing tracks is significantly less-one estimate energy needed by the train. The continuous power at the is 10 times less-than purchasing new high-speed trains rim is 4,000 kilowatts to guarantee a maximum speed of and building dedicated tracks. In addition, the existing 220 kilometers per hour. tracks can still be used for nontilting rolling stock. The Pendolino actuators are controlled by a computer EARLY LEANINGS that receives signals from an accelerometer placed on the The first Pendolino prototype, a single car, was produced lead car to measures lateral acceleration going into the in 1970. Tests were conducted from 1971 to 1973 on the curve. A gyroscope, also on the lead car, confirms that serpentine route between the northwestern Italian towns acceleration is caused by a curve, according to Mazzotto, of Trofarello and Asti as well as the high-speed line be­ and not by the realignment of the train such as from an tween Rome and Naples. The prototype exceeded speeds irregularity in the track. of260 kilometers per hour and breezed through curves 15 Fiat engineers designed the Pendolino active tilting to 30 percent faster than conventional operations. system to automatically lean the body shell of passenger These results were used for the first operational Pen­ cars by a maximum 8 degrees toward the inside of dolino, the ETR-401, a four-car train that served 120 curves, so the Pendolino can compensate up to 1.35 first-class passengers. In this early design, a gyroscope meters per square second of the centrifugal acceleration and an accelerometer were located on each bogie, rather felt by passengers. This permits a Pendolino to run with than on the lead car only, to measure the centrifugal accelerations of 1.8 to 2 meters per square second and forces in a curve. The Italian State R ailways ran the train still remain well within the limits of comfort, deter­ on the Rome- line from 1976 to 1985. Based in mined by railway, engineers to be 0.8 to 1 meters per part on test results from this period, in 1987 Fiat intro­ square second. As a result, the train can negotiate curves duced the Pendolino ETR 450 high-speed ,

ME C HANI C AL ENG INEER I NG JUNE 19 98 79 Italy, Malaysia, , , Spain, and have chosen Pendolino tilting trains for their railways. "Rather than buying into other rail compa­ nies," Mazzotto said, "we typically export the Pendolino technology by teaming up with lo­ cal companies to design trains that fit that country's rail standards, level of crew training, and the local culture and taste." For example, Fiat h as joined forces with Rautaruukki­ Transtech in Qulu, , to build a Finnish version of the ETR 460. The main design changes of the train, known as the S220, Downloaded from http://asmedigitalcollection.asme.org/memagazineselect/article-pdf/120/06/78/6381581/me-1998-jun6.pdf by guest on 26 September 2021 revolved around the Finnish climate. "This in­ volved mechanically protecting the suspensions from ice and snow accumulation, and overpres­ surizing the traction compartments under the Talgo engineers raised the support of their air springs above the center of gravity of the floor to keep dust, snow, and debris out," said coaches to enable the pendular trains to tilt with the pull of gravity as they negotiate curves. Marzio Broda, an aeronautical engineer and which used a gyroscope and accelerometer on the end manager for Fiat's sales to Britain. The S220 door pro­ cars to monitor curves. The tilting mechanism was elec­ files and steps are also heated to prevent ice from building tronically activated. Fiat engineers eliminated both rheo­ up on them. static braking boxes on the roof of this model and anti­ Designing the S220 project was a true technology shimmy shock absorbers. The ETR 450, which can transfer that benefited both Finland and Italy. "Before ac hieve 250 kilo meters per hour, entered commercial this project, Rautaruukki-Transtech only built railway service on the Milan-Rome line in 1988 and carried wagons," Mazzotto said. "The company now manufac­ 220,000 passengers per year-a number that h as in­ tures large, extruded aluminum parts, and assembles creased tenfold today. electrical multiple units as well." The latest generation of Pen doli no train, the ETR 460, Fiat's 1 billion-pound contract with Virgin Rail, an­ was introduced in 1993. This train carries up to 478 other example of such international partnerships, is the passengers at a top speed of 250 kilometers per hour. Each ETR 460 is made up of three traction units, each consisting of two motor cars and one trailer. These in­ dependent traction units provide equal power distribution to the motor cars, thereby ensuring electric-brake efficiency and reliability even at high speed. The mechanical braking system combines pneumatic cylinders on disk brakes and an antiskid system. Fiat designed the ETR 460 bogies to dis­ tribute the low axle weight-an average 14 tons per axle-uniformly along the' length of the train. The 2.7 -meter wheel base of the bogies limits driving forces even on small bends of track. The bogies of the latest Pendolino house the hy­ draulic or electromechanical tilt actuators, leaving space inside the compartments to the passengers.

PARTNERS IN ADAPTATION According to Mazzotto, the account for more than 70 percent of the tilting trains in service, in construction, or on order by rail authorities world­ wide (except for ). Great Britain, The Washington State Department of Transportation uses Talgo pendular trains, shown here out­ the , Finland, Germany, side Tacoma, to cut the travel times of passengers traveling in the Pacific Northwest.

80 JU NE 1998 ME C HANI CA L ENG INEER ING largest export deal for Pendolino. Together with local Patentes Talgo introduced its tilting trains into domestic partner GEe Alsthom , Fi at w ill provide 54 Pendolino service in Spain in 1980, with an international debut a year trains plus m aintenance until M ay 2012. The British later. Currently, the trains are also used in Canada, France, Pendolinos will traverse the West Coast Main Line, con­ Italy, Portugal, and Switzerland. In the United States, the necting London, Birmingham , M anchester, Liverpool, Was hington State D ep artment o f Transportatio n and Glasgow. "Twenty percent of the British live in those (WSDOT) in O lympia leased one Talgo in 1994 and an­ cities [Plus] the towns directly on the route," Broda said. other in 1996 to carry more than a half-million passengers With current train technology, the trip from London to between Seattle and Portland, Ore. , as well as between Glasgow takes 5 hours 20 minutes. By 2002, a Pendolino Seattle and Vancouver, British Columbia. and w ill make the j ourney in 4 W SDOT have purchased hours 20 minutes. Broda four train sets to replace ex­ added that with a line up­ isting leased trains on daily Downloaded from http://asmedigitalcollection.asme.org/memagazineselect/article-pdf/120/06/78/6381581/me-1998-jun6.pdf by guest on 26 September 2021 grade program in 2005, it will Leaning to Retrofit Amtrak se rvice on those complete the trip in 3 hours routes as well as between 50 minutes . The engineer re­ TILTING TRAINS ARE an alternative to pricey dedicated Seattle and Eugen e, Ore. marked that Fiat is targeting track for new high-speed trains, but their cost is still far Talgo will also assemble an from negligible. Retrofitting an active tilting system to its research on newer, light­ existing rolling stock can provide an even less expen­ additional train set in its weight m aterials and more­ sive option for fast train travel. Seattle facility. These trains­ powerful motors to increase Waggonfabrik Talbot in Aachen, Germany, has devel­ part of the first Amtrak/state the speed and reduce the oped the ContRolI active tilting system , which was in­ agreem ent in the nation­ weight of the next-genera­ stalled in 1995 on a 25-year-old VT614 train operated by will be partially constructed tion Pendolino even further. German Railways to test its retrofit applicability. Sintef In­ by Patentes Talgo and com­ strumentation in Oslo, Norway, supplied the electronic pleted at a Pacifica M arine THE TRAIN IN SPAIN components for this first testing version of ContRol I. The system can be used for both high-speed trains and con­ facility in Seattle. Like the P endolinos, the ventional railcars. Each new train will consist trains designed by Patentes "The VT614 was originally designed to tilt approxi­ of two custom coaches with Talgo function like a pen­ mately 4 degrees via air springs, but never operated as up to 26 seats, one cafe car, dulum whe n negotiating a tilting train ," said Heiko Hofkamp, a mechanical engi­ one dining car seating up to curves, able to reach speeds neer and project manager for Talbot's Bogie Depart­ 30 passe ngers, six standard of up to 200 kilometers per ment. "Talbot engineers retrofitted this train set with coaches with up to 36 seats new bogies equipped with the hydraulic tilting cylinders hour. However, rather than that are connected by an antiroll bar." each one service car, and actuators and the additional The first of the VT614 is equipped with one baggage car. Each car is energy required by active the ·gyroscopes and accelerometers needed to measure approximately 44 feet long, tilting trains, th e T al g o the lateral acceleration caused by entering a curve. abou t half as long as most pendular train uses natural These instruments send signals to a central computer Amtrak coaches, and will forces for its tilt. that actuates the hydraulic cylinders with the aid of seat at least four people with slave machines, tilting the cars to a maximum of 7 de­ Engineers raised the plane wheelchairs. The trains are grees. The retrofitted VT614 went through curves with a o f suppo rt of their train's radius of 500 millimeters and maximum cant of 150 sc heduled to enter service large di aphragm air springs millimeters at 132 kilometers per hour, compared with by the end of this year. The w ell above the cente r of 113 kilometers before ContRol1. America n subsidiary plans gravity of the coaches. T hey The retrofitted VT614, which was tested over a two­ to market additional equip­ also positioned two cylindri­ year period , now serves the area in ment in the United States . cal turre ts over the h ea d southern Germany. The American Talgo trains plates of the truck frames to will not exceed 126 kilome- raise the supporting level of ters per hour on the Pacific the springs and act as the springs' auxiliary air reservoir. Northwest rail corridor for so me time-the maximum When a Talgo pendular train enters a curve, the higher according to federal regulations. Their ability to negotiate placement of its springs creates a compressive force on the curves without slowing down is the key, according to interior plane of the springs; tilting the train car to the in­ Theresa Gren, a WSDOT rail communications specialist, . side of the curve by as much as 3.5 degrees. This reduces reducing travel times between Seattle and Portland by 25 the affect of centrifugal force on the passengers. . minutes without increasing maximum speeds limits or In addition , the Talgo trains have one wheel se t be­ constructing track and grade crossing improvem ents. tween each pair of cars to fo rm a single articulated unit T he popularity of getting travelers to their destinations that provides each coach with a stable freedom of move­ fas ter by rail is continuing unab ated throughout the m ent. Depending on the trac k layout, Talgo trains can world, and will further the development of high-speed cut travel times by up to 35 p ~ rce nt compared with con­ trains . T he need to keep costs down and speeds up- us­ ventional, nontilting trains, according to G ustavo Gon­ ing existing track in som etimes m ountainous, often zalez, executive vice president and chief executive offi cer scenic regions-will prove to be the driving force behind of US. subsidiary Talgo Inc. in Bellevue, Was h. tilting trains in the future . •

M EC H AN ICAL ENG I NEE RI NG JU NE 1998 81