advertisement

---

If you’re in charge of communications and signals, you’ve probably asked yourself this question: What’s not to like about light-emitting diode (LED) lamps? They last up to 10 times longer, are brighter and operate at a lower temperature than incandescent bulbs, railroads’ wayside and crossing-arm signal lamp of choice for decades.

Railroads replace thousands of lamps each year, so those are huge advantages that mean higher operating efficiency and lower lifecycle costs. So much so, roads are using LEDs instead of incandescent bulbs in many devices, from signals to passenger-car tail markers to blue safety lights. But there still are a number of roads that remain skeptical.

Cost is one reason, although prices have decreased the past few years, LED suppliers say. Another is reliability. Some railroads have over-estimated the lifespan of an LED lamp, expecting it to last more than 100,000 hours, says Gary Durgin, vice president of strategic business development for LED signal supplier Dialight Corp.

“But it depends on how you apply them,” he says.

In certain applications, an LED lamp might generate too much heat at the back of the light, says Durgin. LEDs generally will last more than 50,000 hours — or up to eight years — in most applications vs. 5,000 hours for an incandescent bulb.

The best way to measure an LED lamp’s reliability is mean time between failure, says Ed McGrattan, VP of sales and marketing for Rail Development Group, which offers the EVERRAY line of LED crossing signals.

For example, Union Pacific Railroad uses an EVERRAY model as a standard crossing lamp and is registering mean time between failure of 1.4 million hours vs. 300,000 hours for the closest LED competitor, says McGrattan.

“We’re no longer competing with incandescents, we’re competing with other LED designs,” he says.

Likes and dislikes

LED suppliers are aiming to successfully compete by minding railroads’ list of do’s and don’ts.

They want suppliers to develop LED lamps that are more reliable, durable and brighter than incandescent bulbs, and offer a wide viewing angle. They’re also seeking lamps they can use in more applications, such as white LEDs to illuminate a station.

But railroads don’t want LEDs that can’t be field tested to identify failures and are susceptible to “phantoms” (signals that appear lit because direct sunlight or a locomotive headlight reflects off the lamp) or “washouts” (signals that appear to have white spots because direct sunlight overpowers the signal’s color).

So, research and development is crucial, suppliers say. And the optimal R&D approach is to stop taking existing LED products and adapt them for the rail industry, says Union Switch & Signal Inc. (US&S) Manager of Field Support Troy Werner.

Railroads want LEDs they can use as an in-kind replacement to existing signal lamps. But you can’t maximize LED service life by “taking a round peg and placing it in a square hole,” he says.

US&S recently developed an LED wayside signal from the ground up to provide a total solution for rail applications, says Werner. The company is just starting to take orders from freight railroads.

To offer a complete package, US&S devised an “integrity” test that — similar to a pulse test conducted on incandescent bulbs — can determine if the LED lamp has failed, says Werner. To date, most LED signals can’t be tested in a similar fashion because they don’t respond to an electrical pulse the same way incandescent bulbs do.

US&S’ LED solution features a curved outer lens designed to eliminate deflection problems, such as washouts; a signal module available in red, yellow, green or white; a constant current regulator; an array that requires less voltage; and a design that calls for smaller gauge wires and less copper wiring, which can be expensive. The company chose the materials and design to significantly reduce installation and maintenance costs, says Werner.

Eye on expenses

At Dialight, LED wayside signals include components designed to trim customers’ maintenance and energy expenses. The signals feature high flux LEDs instead of traditional 5mm LEDs to reduce power consumption, boost performance and extend service life, says Dialight’s Durgin. The company has produced products containing more than 25 million high flux LEDs and hasn’t had a failure attributed to the LED, he says.

Dialight is supplying wayside signals to the Chicago Transit Authority, Greater Cleveland Regional Transit Authority, Miami-Dade Transit and MTA New York City Transit, which recently completed a four-year retrofit requiring more than 60,000 LED signals.

“New York City Transit’s wayside signals are up to 100 years old and they didn’t want to replace the entire units,” says Durgin. “We developed a way to work with their existing optics.”

Dialight also offers 12-inch LED crossing signals and an LED tail marker for passenger cars. The tail markers have been popular the past three years because vibration tends to cause conventional markers to fail after about 4,000 or 5,000 hours vs. more than 50,000 hours for the LED markers, says Durgin.

Dialight currently is developing white LED products to extend the service life of bulbs used to illuminate stations and passenger car interiors. The LEDs would contain no mercury, as used in fluorescent bulbs, and operate at a low temperature, says Durgin. Dialight is testing the LEDs in stations and might complete R&D during the next year.

LEDtronics Inc. is in R&D mode, too. The company continually redesigns or enhances its products to keep up with the evolution of LED chips that are becoming better and brighter every six to nine months, says Marketing Manager Jordon Papanier.

LEDtronics offers LED products for wayside signal, passenger car tail marker and floor lighting, light-rail assembly and other rail applications. The company’s LED bulbs provide optimal value for lumens per watt, operate at cooler and lower temperatures, and last longer than other products, says Papanier.

“We control the LED down to the chip level, and have LED chips molded to our design specifications,” he says.

Because passenger roads are demanding more LED options to replace tubular fluorescent lights in cars, LEDtronics offers a line of LED tube lights.

GE Lumination is trying to meet passenger railroads’ demand of a different sort: less bright LED signals that can be used in tunnels. The company offers a frosted or smoked lens to tone down the brightness and make the signal more comfortable for an engineer to look at, says Chris Bender, GE Lumination’s product manager-rail.

The company has offered LED level crossing signals since 1996, and the current model introduced in 2002 is used by more than a dozen freight and passenger railroads.

Since 1999, GE Lumination also has marketed LED colorlight signals. Designed for vital applications, the wayside signals are compatible with six different controllers supplied by four companies, says Bender. In addition, the company offers different types of optical lensing to provide LED wayside signals that are visible from 1,500 feet to more than 5,000 feet away, depending on a customer’s preference, he says.

From one end to the other

Currently, GE Lumination is developing a 10-volt alternating current (AC) lamp retrofit solution so a railroad can replace incandescent signals along an entire line at one time, even ones that use AC relays.

“Typically, railroads replace incandescents with LEDs when they upgrade controllers,” says Bender. “This will tie into our universal retrofit capability by enabling them to replace signals along an entire line without changing controllers.”

Velcorp/GEMS is capping off some R&D of its own.

In March, the company expects to introduce an upgraded GEMSTAR^® LED replacement bulb, which can be used in crossing-gate arm, flasher head and non-vital signal applications.

Designed to eliminate phantom signals, the GEMSTAR currently is available in an operating range from 8.5 to 30 volts in either AC or direct current (DC).

Beginning next month, the operating range will expand to between 6 and 75 volts in AC or DC, says Velcorp/GEMS General Manager John Curtin.

The firm also offers the GEMSGATE™ line of LED gate arm lights and light kits, and LED color indicators for blue flag, track switch and other applications.

Velcorp/GEMS is developing an upgraded LED board that will offer 120 volts without a transformer vs. the current 24 volts without a transformer. In addition, the company is working to provide LED products with a lens offering the best focal presentation because railroads want LED lamps to look the same as incandescent lights, says Curtin.

“It’s a compromise between an inexpensive way to build an LED and still give a good focal presentation that can been seen at a great distance,” he says.

Velcorp/GEMS’ products continue to feature a single LED or one LED on each end to reduce power consumption and cost (“LEDs aren’t cheap,” says Curtin).

Lower power consumption is a prime objective of Rail Development Group’s (RDG) EVERRAY LED signals. So is reliability. The crossing signal is designed to degrade slowly, losing less than 1 percent of its intensity over time compared with 50 percent for other LEDs, says RDG’s McGrattan.

The EVERRAY also offers a wide viewing angle, a 0.26-inch-thick polycarbonate lens to resist vandalism, and a lower current draw to reduce wear and tear on controllers and relays.

Last year, RDG re-branded its LED crossing signals — which have been in field service since 2000 — as EVERRAY to stress the signals’ reliability, durability and visibility, says McGrattan. UP, Kansas City Southern and Amtrak have specified the EVERRAY as their standard crossing lamp.

“Three other railroads are analyzing the EVERRAY as a potential standard,” says McGrattan.

Meanwhile, Lumastrobe Warning Lights continues to expand its line of portable, battery-operated LED blue signal protection lights to meet railroads’ needs. The company recently introduced a single-tier, six-LED, solar-powered light offering 360-degree visibility and multiple mounting options. In March, a three-tier, 18-LED version will be available.

In addition, Lumastrobe later this month plans to introduce a 12-inch-long, cylindrical-shaped light featuring a magnetic base at one end and a flashlight at the other. The company currently is developing remote-controlled uni- and bi-direction signals designed to enable a worker to activate multiple lights with a key fob controller.

Market conditions

Translight Corp. is readying a new LED product for the rail industry, too. In the second quarter, the company expects to begin marketing an LED locomotive headlight designed to mount in a reflector and be four times brighter than an incandescent light.

The LED headlight — which will be Translight’s first LED product — is based on aircraft landing light technology, says General Manager George Koester.

As LED products continue to evolve, it won’t be long before all railroads are using the lamps in some fashion — perhaps as soon as two years, says RDG’s McGrattan.

But two issues need to be resolved first. The Federal Railroad Administration hasn’t determined what constitutes an LED failure.

“Is it 20 percent, 50 percent or 70 percent of the LEDs out? The railroads are asking for a definition,” says McGrattan.

In addition, the lumens per watt range needs to reach the right balance to offer LEDs with the best power savings, a long life to 50,000 hours and an affordable price, says LEDtronics’ Papanier. Currently, the range is between 60 lumens per watt for 5mm LEDs and 150 lumens per watt for high-power LEDs.

“It may take five years for LEDs to reach this balance,” he says.

Correction April 2008 This article (“An illuminating experience”) mischaracterized TransLight Corp.’s new LED products. TransLight is readying a new patent pending LED headlight for locomotives and other train maintenance equipment. The patent covers the use of this device for all other similar headlight or lighting devices that benefit from projected beam patterns applications, rather than bright surface illuminations with limited projected beam patterns. At this time, TransLight believes that projected beam patterns are essential for train and vehicle traffic control signal for penetrating inclement weather conditions, and with incandescent lamps lasting up to 50,000 and 100,000 hours, the extra cost for LEDs may not be justifiable, especially with the railroad paying a much higher cost for replacing failed LEDs vs. incandescent lamps. Therefore, TransLight has a patent pending reflector that mounts on the generic incandescent lamps for wayside color-light signals that increases the beam pattern candela by up to four times. They also have designed a patent pending LED with a miniature reflector that mounts into existing lamp sockets and has a focal distance that mates with the existing designed optical color light lens set of existing color light signals. This concept means only the lamp will be replaced with the reflectorized LED configuration, thereby saving railroads the cost of replacing signal fixtures or lens sets.