March 20, 2015
» Blacksburg Transit, Blacksburg, VA, has an opening for a transit director. [More]
» The Birmingham-Jefferson County (AL) Transit Authority seeks a director of operations. [More]
» MTA New York City Transit is soliciting contracts for 231 low floor 60-foot articulated buses with an option of up to another 300 buses. [More]
View more Classified Ads »
TO PLACE AN AD: E-mail the requested date(s) of publication to: Mailing address is: Passenger Transport, 1666 K Street, NW, Washington, DC 20006. Ad copy is not accepted by phone. DEADLINE: 3 p.m. EST, Friday, one week prior to publication date. INFORMATION: Phone (202) 496-4877.

3-D Printing: Breaking the Mold

Special to Passenger Transport

An engineer recently printed a working automobile engine and transmission on a 3-D printer. Surgeons can now 3-D print stents, splints, prosthetics and even parts of the human skull, knee or airway. It seems only logical that 3-D printing should begin to make its way into public transportation, holding the potential to lower costs and increase the speed of design, production and maintenance of public transit systems.

"I see 3-D printing as having a big impact on transit agencies in the near future. The ability to control their own supply chain and destiny when it comes to operations is huge," said Lou Cripps, administrator, asset management, for the Regional Transportation District in Denver. "RTD currently does not utilize any 3-D printing, but on the side I've been tinkering with the technology for a little while. This technology has the potential to revolutionize the way most things are made."

A 3-D printer, first developed in the 1980s, prints ink not on a piece of paper in two dimensions, but outputs layers upon layers so that a three-dimensional object is eventually created out of materials like plastic, ceramic or metal.

Currently, 3-D printing is seen to potentially benefit public transit by lowering the cost of replacing hard-to-find parts, improving the prototyping and design process, giving more flexibility to maintenance shops, reducing the need for parts storage and creating more Buy America opportunities.

Given the way 3-D printing is changing other manufacturing sectors--and becoming commonplace for everyday products like eyeglasses, shoes, jewelry and tools--there are likely applications that industry experts haven't yet imagined.

However, before public transit agencies can leap into 3-D printing, there are challenges to overcome, including the reliability, performance and longevity of the printed materials, their compliance with regulations and standards and concerns about infringing on trademarks, patents or other intellectual property.

"There is a huge liability attached to anything that is safety-related. To do all that testing is very expensive," said Peter Vrinceanu, vehicle maintenance chief at the King County Metro Transit Division in Seattle, who is waiting for clearance from his legal department before pursuing 3-D printing.

That doesn't mean that Vrinceanu doesn't see the potential of 3-D printing. King County Metro is constantly looking for possible retrofits and changes for its fleet. It could save time and expense to simply print new designs or cosmetic items such as brackets, clamps or decorative panels.

In addition, the agency owns a fleet of historical buses dating to the World War II era that are used for special events. Since most parts are no longer manufactured, it can be costly and time-consuming to hand-make replacement components.

"A large number of these coaches do not run because they have missing parts. The parts are one-of-a kind, so there's lots of research to make a part and they're very expensive," he said. "It's part of our history, it's part of who we are. We would like to present the fleet to more people so they have a better understanding of what we are like today and how we got here."

In some situations, a small 3-D-printed part could solve a big problem. For instance, the plastic parts inside a farebox may not cost more than a few dollars, but they could keep a bigger component costing as much as $75,000 from being usable.

"If it's a major component, and the whole coach has to be parked and not used, you have a million-dollar piece of equipment that is not being used for so many days or weeks," Vrinceanu said. "You can have the same bus not being usable because a small bracket is missing, that's a safety item."

Whenever a part is created or printed on-site, it could take a step towards compliance with Buy America provisions. "It will help them if they make the parts in house; the part could be labeled as made in the United States. It will help them meet the magic number," he said.

The technology could also lessen the need for parts storage, which ties up space and capital, if agencies could simply print on demand when they need replacement parts.

"In any industry, it looks like everybody is walking away from storing parts, everybody wants just-in-time parts, so the inventory is very low in any transit agency. If we have a way to produce it in house, quickly, it would always be a benefit," he said, noting that recently he had to wait six weeks to get a simple decal from the manufacturer, something that could potentially be printed in house in just a couple of hours.

The Los Angeles County Metropolitan Transportation Authority (Metro) could potentially benefit from 3-D printing of small parts and components, which currently are made on a CNC machine, agreed Patrick Astredo, deputy executive officer. "We do see some limited opportunities for us to use 3-D printing as the quality of the materials improves," Astredo said. "Some clips on older vehicles are very difficult to come by and we could just print them out."

Another opportunity is to validate the design and fit of parts, he said. An employee could draw a system with 3-D CAD software, print a model and make sure it works before committing to the actual product.

That's exactly what Conductix engineers did in designing a new insulating cover for the third rail in New York City's Second Avenue subway project. After 18 months of design, drawings and consultation, they felt they were close enough to produce a test part. But instead of taking six weeks to create a tool, ordering specialized materials at large enough volume for a minimum run and making the part itself, they simply printed a six-inch section of the cover. They went from the final design stage to rapid prototyping within a day.

"We went back and forth five or six times over the design on paper; we were debating over thickness, and I said, 'Let me send you something to put in your hands'," said Ryan Frost, a development engineer in Conductix's Omaha headquarters. "The next communication we heard was the purchase order. It definitely cut through a lot, maybe six to 10 weeks of time saved."

Since the cover needs to fit exactly over the third rail--which itself is different from one subway system to the next--the agency needed to know that the design was perfect before committing.

"Anything that facilitates the rather involved process of design, verification and validation is very, very helpful. It's critical to the nature of the transit business," said Keith Forman, global director of transit. "Time is money."

In addition, 3-D printing can be helpful in creating installation jigs, drill jigs or other fixtures that hold equipment in place for maintenance purposes, Forman said, noting that sometimes it can take more time tooling the fixture than the repair itself.

"ÒIf you look at all the activities where there's some manipulation, some positioning, some aligning, where this technology [could] be applied, there are incredible amounts of things," he said.

Early 3-D printers only created flimsy products. Nowadays, they can be as strong as injection molded parts, and the newest 3-D printers can print metal or other non-plastic objects. "The quality of the prints at the commercial level is already better than injection molding and already as good as some casting and machine parts," said RTD's Cripps.

Philadelphia-based Bentech uses 3-D printing in 40 percent to 50 percent of its production processes for railcar and bus handrails and fittings, to model and design parts for casting more quickly. Engineers need to adjust for some shrinkage and are learning the conversion factors between the 3-D printed part and the final product.

"It does save us anywhere from two to three weeks in new parts. Prior to that time, prototypes had to be carved out of wood," said Robert Benninghoff, head of sales and engineering. "Machines can be left to run overnight. They can be left on a Friday night and the part is ready on Monday morning. People have a nasty habit of wanting to eat, sleep and watch a baseball game. That does allow us the flexibility to do more iterations at a much reduced cost."

Cripps sees applications in public transit systems' accessibility programs. "The local agencies for a few thousand dollars might be able to print their own braille or make customized accessibility features for a low cost. The cost for uniqueness goes down," he said. "You can customize things to different users .. if you have parts that travel with operators to make things more ergonomic for them or passengers who have a disability."

When agencies are reaching out to the public with a new station design, they could rapidly produce multiple different styles that people can see and touch, rather than having to imagine from a two-dimensional rendering. These kinds of applications are a safer way for agencies to begin to experiment with 3-D printing, since they are one-off or original designs.

Raul V. Bravo + Associates is experimenting with 3-D printing in the design and production process for trucks, the running gear for passenger rail equipment. But rather than investing in equipment and materials capable of printing products that could be used in railcars, the firm decided to focus on 3-D printing that will facilitate modeling, conceptualizing and integration for upcoming projects, said Vice President Claudio Bravo.

"There are certain technologies where you can have what they call 'end user parts'; you print something and then you can actually use it on a component, bolted onto a system or vehicle," Bravo said. "We opted to go with the technology and material that doesn't allow for end user parts."

Thus far, the firm sees three primary uses for 3-D printing. First, it can produce a scale model that customers can display to make it easier to understand the design, rather than having to visualize the end result. "It has a certain value to suppliers and consultants who can display models in their public spaces," he said.

Second, 3-D printing can speed the design process by enabling engineers to experiment with different physical interfaces and develop concepts that might prove fruitful for the final design, whether for a system, component or vehicle. "We can use it during design review meetings to help communicate to the group involved in those design reviews where we stand at any moment," Bravo said.

Finally, 3-D printing can let the company test how different systems come together physically so that any incompatibility or problems can be resolved early on. "That's how we're hoping and planning to roll out our technology," he said. "It's going to be an evolution in the industry."

Indeed, with the quality issues seeming to be on a path toward resolution, the trademark and patent concerns could be the next challenge for agencies interested in 3-D printing of parts, especially as a substitute for expensive, hard-to-get replacements.

"The issue has not been addressed in courts yet," said Vrinceanu. "The popular example is, if we are producing Mickey Mouse, who is Disney going to sue? Are they going to sue us, as an agency, because we're producing it or the printer manufacturer, whoever produced the file from software? The lawyers are looking at past practices and it went both ways."

It's one thing when a part is completely obsolete. The real problem arises with those parts that are available but are cost-prohibitive to buy. "Manufacturers are making a ton of money on replacement parts. We are not foreseeing them giving this up without a fight," said Vrinceanu.

It's far more difficult to reverse engineer a part and carve it out of wood, versus using a 3-D scanner to create an image of the part and then simply print it out. "Case law, and public opinion in these areas, and many others we cannot even yet fathom will have to be developed to determine the ethics of what can and cannot be done," Cripps said.

Conductix's Forman pointed out some companies are already reverse engineering parts. "Certainly 3-D printing could facilitate that, but what do you do about that? You can either try to resist it or you can try to use that technology to your advantage," he said. "In the long run the technology's advantages far outweigh the disadvantages."

Perhaps a system will develop in which public transit agencies could print a replacement part if they pay a royalty to the original manufacturer for each unit. "We have to work with manufacturers so that maybe when we purchase something, each time you print a copy of that part there's a payment that's given to them. It's almost usage on demand and payment tied to that usage," he said.

But that kind of a legal framework is currently just theoretical. "Some of this stuff needs to be vetted out," Astredo said. "As a public agency, we don't like to be on the bleeding edge of technology. We want to have something that's proven and a process that's already in place and makes sense for us from a financial point of view."

Then there's the whole issue of regulation and standards for reliability of materials. Even though 3-D printed products are becoming stronger and more durable, they can't replace existing materials until the regulators and standard-setting bodies decree that they are okay.

Public transit agencies foresee another long process before the raw materials used for 3-D printing of a molded plastic part are deemed equivalent to the regulator-designated grade of plastic currently in use.

"Most components are made out of steel or plastics and they're a specified grade. A lot of these 3-D printer anufacturers create their own materials and they're PVC-like," said Conductix's Frost. "When you get to a point where 3-D materials are standardized and all these bodies have approved them, [then] that would open up the market greatly."

Until that time, the best opportunities for public transit agencies will be for small interior parts on buses and on trains, signage, accessibility improvements and the like. "It's one of those things that I think is definitely going to take off. A 3-D printer will be a mainstay in a lot of shops but it's just a matter of how many years from now," Astredo said. "We've got to get past the novelty phase and into heavy production and usage."

Not only could 3-D printing lower costs, speed design and production, and offer other benefits, it could potentially unleash new areas of innovation as engineers and designers are able to print and test objects that previously were simply impossible to create. "We will be able to design and build parts that could never have been machined, cast or assembled," Cripps said.

Indeed, 3-D printing could revolutionize logistics patterns, the flow of materials and even how parts rooms are designed. "You probably will have to have on-site fulfillment. We would be able to bring manufacturing to areas so bulk materials came in and the parts were made here," he said. "I do see this also changing patterns in logistics shipping because if we're decentralizing some of the manufacturing, we see less and less transportation of goods and more just raw materials."

Change could come more quickly than one might imagine, as innovators build on each others' advances. "The idea is that as the cost comes down, these things will be as common as copy machines. We've got years to go, not decades," Cripps predicted.





A 12-inch 3-D model produced by Raul Bravo and Associates of a Bradken truck. Photo courtesy of Bradken. 

A third rail cover. Photo supplied by Conductix. 

A third rail insulator. Photo supplied by Conductix. 

A tee fitting made from a pattern printed by a 3-D modeling machine. Photo supplied by Bentech. 

What's Your Story?
Is your agency or business working with 3-D printing? Let Passenger Transport know! Reach us by clicking here.
« Previous Article
Return to Top
Next Article »

© Copyright American Public Transportation Association
1666 K Street NW, Washington, DC 20006
Telephone (202) 496-4882 • Fax (202) 496-4321
Print Version | Search Back Issues | Contact Us | Unsubscribe
Twitter Flickr Blog YouTube Facebook