The Pantograph Barrier, Part 4 of 4: The Balanced Force Pantograph Solution

Part Four will conclude this series and focus on how the Pantograph Barrier can be eliminated and increase train speed beyond 220 MPH. In review, Part Three of this series discussed why having electrified passenger trains that can go beyond 220 MPH is important to our infrastructure and can change the way people travel. 

All electric trains require some system to continuously transfer large amounts of electrical current from a stationary wire (Catenary or third rail) to the moving train.  In order to get rid of the pantograph speed barriers caused by vertical displacement of the wire, a new form of catenary is needed that will not place uneven force on the catenary wire while still allowing for the transfer of electricity. Any force on the contact wire must be balanced by an equal and opposite force.

The Balanced Force Pantograph (BFP) is a new catenary and pantograph system that contacts the wire horizontally using two sets of contacts that face each other, as opposed to the single wire contacting vertically in current systems.

The shape and tensioning system of current catenary wire are not ideal for horizontal contact. So a new type of wire is required that has flat surfaces on both sides for the contacts to ride on.  This configuration also permits the increase in the size of the electrical contact surface, and thus permitting more consistent current transfer.

The BFP system must work with traditional pantographs as well to be commercially successful. It is not practical to build all new high speed tracks and catenary for the exclusive use of locomotives equipped with a BFP system. In addition, it would be extraordinarily difficult to build a completely new right-of-way for 220+ MPH service. This is actually an issue that other solutions, such as the Hyperloop, have not addressed yet. In the United States, it is typical for all speeds of train service to share tracks. The BFP system must accommodate both current electric locomotives using traditional pantographs and locomotives fitted with the new BFP technology. The BFP system addresses this by making the bottom of its catenary wire curved so that it is similar to the profile of current catenary wire and supports the use of current pantographs.

High speed trains do not travel at top speed for many parts of their journey, because the geometric realities of build tracks and practical limits on acceleration and deceleration. Typically, geography and congestion force trains to slow down as they approach intermediate stations, interlocks, densely populated cities, and stations. The BFP is not needed at slower speeds below 200 MPH, so it only needs to be installed on sections of track that allow for 180+ MPH operations. This allows lower-speed trains using traditional pantograph technology and high speed trains dual equipped with current and BFPs to share tracks. Conventional catenary wire will continue to be used on sections of track that are not suitable for high speed operation. The BFP wire technology is designed to be retrofitted onto existing catenary systems and will permit seamless transitions from one catenary technology to the other.

Figure 1 depicts a conceptual design for the Balanced Force Pantograph Overhead Catenary System Wire. The wire has become more of a blade that permits contact pads on both sides of the wire. The forces holding the contact pads in place is equal and opposite. No unresolved force is applied to the OCS. The bottom of the blade provides a contact surface that serves as a conventional OCS wire.

Figure 2 shows an elevation of the side of the Balanced Force Pantograph with the electrical contact pads in touch with the Balanced Force Wire. The pantograph includes mechanisms that move the contact pads up / down and right / left to follow the wire.

Figure 3 shows a locomotive with both conventional and Forced Barrier Pantographs. The pantograph control system automatically transitions from one technology to the other with no break in operation as the locomotive accelerates above 150 MPH or coasts to below 180 MPH.

Figure 4 and 5 are a block diagram indicating the elements of the control pantograph system. It includes machine vision and laser sensors to track the OCS Wire and provide position information to the literal and vertical control actuators.

Some reviewers have been skeptical that the proposed Balanced Force Pantograph and Overhead Catenary System concept can be made to work with current technology. It is possible to design and build a pantograph that can follow a wire in 3 dimensions and hold contact with the wire while traveling at 300 MPH. It will not be easy, however, tracking conventional catenary at 180 MPH and in three dimensions is already part of a catenary inspections in Japan.

Other skeptics have expressed concern that the potential cost of the BFP is too high to make it feasible. The BFP system is undoubtedly more expensive to install than current catenary technology, but it allows for an increase in train operating speeds. This can have an enormous effect on the desirability of train travel and competitiveness with air travel. Building high speed rail is already extremely expensive, and the balanced force pantograph does not significantly increase that cost. It does, however, improve the economics of high speed rail which improves the viability of High Speed Rail projects.

The intention of this series is to initiate a more extended discussion of the future speed of High Speed Train Travel and to spark a discussion of the Balanced Force Pantograph system.  Increasing the possible operating speeds of trains by solving the Pantograph Barrier is part of the path to designing and building trains that can more effectively compete with air travel and other future technologies such as the Hyperloop.

Click the links below to read parts one through three of this series.

Part 1 of 4: Of Pantographs & Wires

Part 2 of 4: Effects & Consequences

Part 3 of 4: Why Speed Matters

   

Frank has over 45 years of diverse experience as a Professional Engineer and is registered in 17 states. His experience includes: electric power generation and distribution, microwave communications, public safety radio, SCADA, fiber optic communications and railroad communications. Currently, Frank is a Lead Consultant with MACRO, a division of Ross & Baruzzini, in Chalfont, Pennsylvania. Over the last decade and a half he has provided consulting and engineering services to: SEPTA, AMTRAK, PANYNJ, Caltrain, NJ Transit, Delaware Port Authority, San Diego Transit and many others. In addition, he has 4 patents relating to railroad technology.

Designing Modern Park Facilities: Part 1 of 3 Internal and External Building Components – The Unsung Heroes of Park Facilities

This post was originally published on May 6, 2018 and updated on December 27, 2021.

The National Recreation and Park Association (NPRA) estimates that Americans visit their local parks and recreation facilities an average of 29 times per year. Forest Park, in St. Louis, attracts 13 million visitors annually, and one-day events such as the Great Forest Park Balloon Race attracts thousands of visitors in a single day.

With this type of high usage by the general public, it’s no wonder that park facilities, such as pavilions and comfort stations, can take a real beating and be the unfortunate targets of graffiti and other types of vandalism.

From an architecture and engineering perspective, designing park and recreation facilities is a challenging but rewarding task, especially when their structures are put to the test and successfully survive the rigors of visitors, time, and the elements.

This brings us to part one of our three-part series – internal and external building components, the real unsung heroes of park facilities serving as the backbone of solid park design:

  • Non-absorbent, no-smell interiors with appropriate finishes and fixtures for longevity and ease of maintenance
  • Maintenance free, graffiti-resistant building materials and finishes with appropriate barrier coatings to promote preventative maintenance such as non-stick, non-mark paints and coatings or polyurethanes
  • Durable, exterior grade, high-performance light fixtures with freeze-proof components and vandal- resistant lenses
  • Vandal-resistant, National Fire Protection Association (NFPA) compliant electrical power and distribution systems properly bonded and grounded within rigid water-tight conduits and incorporation of lightning protection systems with the ground grid
  • Environmentally-friendly composting toilets for non-urban parks that treat human excreta by composting or aerobic decomposition that eliminates clogged toilets and flooded bathrooms
  • Green eco-friendly mechanical, electrical and plumbing systems that provide high performance and low operating costs as well as low maintenance and easy serviceability
  • ADA Standards for Accessibility for use by individuals with disabilities per the Code of Federal Regulations
  • Mechanical, electrical and plumbing utility infrastructure components (utility sinks, hose bib, trench drains, floor drains and electric outlets) that are placed in hard-to-reach areas for the general public, yet easily accessible to maintenance personnel

Ross & Baruzzini recently designed a new concession stand/comfort station and pavilion for the City of St. Louis Forest Park that successfully integrates the aforementioned design features, resulting in practical structures built to withstand high usage for many years to come.

Stay tuned for part two of our three-part park series which compares urban vs. rural park planning from architect/engineer and local landscape architect perspectives.

Main photography via Forest Park Forever.