MSOE Hosts First Design Review of Innovative STEM Education Initiative Based Around Milwaukee County Zoo Steam Train

The Milwaukee School of Engineering CREATE Institute hosted the first design review of an innovative, multi- high school STEM engineering challenge this week. The program, which is headed up by Learn Deep in collaboration with the Milwaukee County Zoo and the Coalition for Sustainable Rail (CSR) seeks to pilot an innovative education initiative that partners area high schools with colleges to bolster STEM education. With the participation of six local high schools, five colleges, and multiple industry sponsors, this initiative seeks to leverage the Zoo train to spur meaningful tech education. The goal of the initiative is to help schools build the capacity and relationships to collaborate across districts with community partners to take on real world engineering challenges. 

“The Zoo’s North Shore Bank Safari Train is one of our most beloved attractions, and something which hundreds of thousands of visitors ride each year,” explained Chuck Wikenhauser, Director of the Milwaukee County Zoo. “We are excited to have the Zoo train serve as a tool to engage local schools and universities in a collaborative learning opportunity that will both improve our railroad at the Zoo and create lasting learning experiences.”

During the project kickoff, Joost Allard and Pete Reynolds of LearnDeep addressed the crowd of 85 high school students and 10 industry reviewers.

The driving vision for this effort is to have Milwaukee area students design and fabricate an advanced steam locomotive powered by renewable fuels. That’s too big a challenge to take on off the bat, so over the next few years, students will complete projects of increasing complexity related to the Zoo train. Students are working this year to design and fabricate a replacement for the wooden water tower that services the steam train.

“Our goal with Learn Deep is to find opportunities to build connections across schools and industry to develop meaningful learning opportunities, and this effort with the Milwaukee County Zoo is our most exciting initiative to-date,” said Pete Reynolds, Co-Founder of Learn Deep. “The initiative taps into the energy and enthusiasm of educators who want to see their students do great things. It has also allowed industry and university partners to easily see where they can plug in to support innovative efforts in education that have a community-wide impact.”

This semester, students completed conceptual designs for a new water tower. They shared their designs, decisions, and processes with teams from other schools before a review panel hosted by MSOE on December 10th. In spring 2019, students will take what they learned from the review session to complete detailed designs which will be presented for review at an event hosted by UWM in early May. At that event a design approach will be selected.

“We strive to find opportunities for our students to connect with the community and dive deeper into developing both the mindset and skillset they need to become responsible professionals.  MSOE’s faculty often work directly with community partners like the Milwaukee County Zoo.  However, this project offers a unique opportunity for our students to mentor high school students while working to add value to the community.  All stakeholders involved owe this opportunity to the coordination efforts and vision of Learn Deep,” explained MSOE CREATE Institute Director DeAnna Leitzke, P.E. “Furthermore, this project is unique in that it allows high school students to interact with clients, practitioners, tradespeople, college students, and professors to solve a real world problem. This enables high school students to experience both academia and the trades, helping to inform their decisions post high school in a way that encourages equally the pursuit of higher education or skilled craft.”

Detailed engineering will happen in a boot camp over the summer, and schools will fabricate parts during the fall semester of 2019, for installation by spring of 2020. Fall 2019 will also see the kick off for the next phase of the project-- design and fabrication of an automated coal handling system.

Interesting the future in the rail industry is one of the key goals of this initiative. Kalmbach Publishing Co. was kind enough to donate dozens of magazines for the students to take home with them.

Throughout the effort, participating students have the chance to visit university and industry partners for on-site workshops related to the project. This semester students attended a design thinking workshop hosted by Briggs & Stratton’s Concept Design Team, and a workshop on structural engineering considerations for the water tower hosted by MSOE. Teams are also supported by engineering students from partner institutions, as well as a pool of industry mentors.

“Following previous biofuel research we did with the Milwaukee County Zoo with its steam locomotives, we are excited to assist in this education program, in large part as it serves as a means to familiarize a new generation with railroads,” said CSR President Davidson Ward. “The rail industry overall is facing challenges attracting new talent in the face of retiring baby boomers, and the ability to engage a new generation with the concept of railroading, even on the scale of the Zoo train, is something that is both important and meaningful.”

Learn Deep serves as the overall coordinator of the program, with support from the Zoological Society of Milwaukee. The partners seek the involvement, engagement, and support of local industries and philanthropists. Should you be interested in learning more and/or supporting this work, reach out to Pete Reynolds, Learn Deep.

Biofuel Tests at Milwaukee Zoo Train a Success, CSR and NRRI Look Ahead to Standard Gauge Trials

Milwaukee County Zoo train on a trial - the first locomotive is burning 100% torrefied biomass, and the trailing locomotive is burning a 50/50 blend of torrefied biomass and coal.

Two steam locomotives at the Milwaukee County Zoo were fueled with a renewable wood-based solid fuel last week to reduce fossil coal emissions, and the tests were a success.

The Coalition for Sustainable Rail (CSR) and the Natural Resources Research Institute (NRRI) completed a final series of three biofuel trials following more than a year and a half of development of the fuel at NRRI’s Renewable Energy Lab in Coleraine, Minn. Thanks to the generosity of the Milwaukee County Zoo, its small 15-inch gauge railroad has served as a demonstration platform for CSR and NRRI to see how a wood-based torrefied biomass fuel product burns in locomotive-style boilers. Tests in June and October 2016 revealed that the biofuel could make sufficient steam, but improper pelletizing methods resulted in spark emissions from the locomotive.

“Following the first trials, our researchers set about devising a better method to densify the material, including acquiring an industrial scale densification machine that we installed at our lab in Coleraine,” explained NRRI Associate Director, and CSR Board Member, Don Fosnacht, Ph.D. “Combined with a food-grade binding agent, we were able to make dense, pill-shaped pellets for use with these Zoo test trials that burned exactly like coal.”

No. 1924 hauls the test train up the steepest grade on the Zoo railroad burning 100% torrefied biomass.

NRRI is currently researching the opportunities in “torrefied biomass,” a wood-based biofuel that is made in a kiln not unlike a coffee roaster. After being “roasted,” the wood is transformed into a fuel that burns and reacts much like coal,  with virtually no heavy metal pollutants and reduced carbon emissions. NRRI provided three blends of torrefied biomass to the Zoo for testing: 1) a blend of 99 percent torrefied biomass and 1 percent binder agent; 2) a blend of 49.5 percent torrefied biomass, 49.5 percent Powder River Basin coal, and 1 percent binder; and 3) a 100 percent torrefied biomass pellet with no binder. Each of the fuels was tested in the Zoo train locomotives, and two were found to be ideal stand-in fuels for fossil coal.

Pre-blended torrefied biomass / Powder River Basin fuel pellets ready to load in the tender of No. 1924.

“The torrefied biomass with binder, and the 50/50 blend of coal and biofuel, worked quite well in both locomotives,” said CSR President Davidson Ward. “Both fuels burned nearly identical to coal, including building a decent coal bed on the grates and maintaining pressure under a wide variety of operational circumstances, while being nearly smoke and odor free.”

Initial temperature data also indicate that the biofuel heating value is equal to coal. The maximum firebox temperatures recorded during the biofuel trials were in excess of 2,100 degrees Fahrenheit (1149 Degrees Celcius).

“I am quite impressed with what I saw from this round of biofuel testing, and I look forward to burning it in our steam locomotive,” said Zach Hall, Steam Operations manager at the Everett Railroad, who was on site to participate in the tests. “From my observations, both the biomass with binder and 50/50 blend of fuel will do just fine to make steam and minimize smoke, both of which are good things in my book.”

CSR and NRRI are ramping up for the next round of tests: manufacturing 10 tons of fuel for use by Everett Railroad steam locomotive No. 11 early next year. In support of these tests, CSR is undergoing a matching grant fundraising process, whereby donations to the non-profit made between now and December 15 will be matched dollar-for-dollar (up to $10,000).  

Zoo Tests: a sneak peek

The Coalition for Sustainable Rail, in conjunction with staff from the Natural Resources Research Institute, completed a third round of torrefied biomass fuel tests with the steam locomotives at the Milwaukee County Zoo this past Monday.  CSR will be providing more details about the findings of that research next week but, in short, it was a success!

Until then, check out the following video of Zoo train 4-6-2 No. 1924 hauling our test train. The locomotive is burning torrefied biomass fuel.

The deep "humming" noise is the locomotive "drumming." Similar to pulse jet engines, the fuel is generating so much combustable matter that the firebox is consuming more air than it can bring in at one time. As air comes through the firebed, it flash ignites, causing a small "boom." Multiply this by hundreds of bursts of air coming through the firebed at once, you get drumming. This is alleviated through better ash pan design, installing overfire tubes (like most late-model steam engines), or cracking the door a bit. Notice that the noise stops when the engineer opens the door to shovel each scoop of fuel into the firebox.

Locomotive Biofuel Testing in 2016 - a detailed review

Milwaukee County Zoo train locomotive No. 1924 hauls its train up the ~3% shop spur track burning 100% torrefied biomass. This image shows the exhaust at its approximate darkest during the testing in October.

Introduction

Entities working to provide biofuel to power plants are faced with the classic “chicken or egg” dilemma. Biofuel manufacturers need to have guaranteed orders for fuel from power plants to finance installation of fuel processing equipment, but power plants wont agree to order fuel until they can run tests, requiring hundreds of thousands of pounds of fuel that can only be made by the very equipment those manufacturers seek to install. 

The Natural Resources Research Institute (NRRI), a collaborator with CSR, decided to go ahead and buy an “egg” to kick-start development - it purchased an industrial-scale biofuel reactor, in part thanks to CSR, and just recently completed commissioning and testing of the fuel. 

We were fortunate at CSR to receive the very first load of torrefied biomass fuel from the NRRI reactor. After years of installation and preparation work, NRRI produced the first two 55 gallon barrels full of fuel for Zoo tests, 500 pounds in total. The path to get to those first 500 pounds was certainly a quest, but the results of the tests made the process entirely worth it!

This panorama shows the torrefaction reactor (center) as sited at NRRI's Coleraine Lab, a former Oliver Iron Mining Company locomotive shop.

Testing Round One

In early 2016, CSR began thinking of locations where it might be able to test torrefied biomass fuel in a steam locomotive boiler. At that time, NRRI was nearing completion of the installation of its reactor, and the belief was that fuel would be ready for testing by June.

Similar to the situation of making enough fuel for power plants, a standard gauge locomotive often requires between five and thirty-five tons of coal to operate. Making a batch of fuel that large for a set of tests would be both time consuming and expensive. Searching for a more manageable size,  we decided that Milwaukee County Zoo, which operates a 15 inch gauge steam railroad with a locomotive of similar draft and boiler proportion to the those used in preservation around the U.S., would be an ideal test environment.

Our team reached out to Ken Ristow, whose job it is to maintain and operate the Zoo train. Ristow is no stranger to mainline steam, having been involved in the preservation of, and serving as the engineer on, such locomotives as Soo Line 1003 (1913 built 2-8-2), C&NW 1385 (1907 built 4-6-0) Soo Line 2719 (1923 built 4-6-2) and the Nickel Plate 765 (1944 built 2-8-4). 

Ken Ristow is at the throttle of Soo Line 1003 as it races towards Hartford, Wisconsin, for its annual Christmas display in November 2015.

Ristow worked with Zoo management to approve CSR’s use of its equipment for testing. In short time, CSR was granted unencumbered access to the Zoo train equipment and its 1.2 mile-long railroad. 

As the test date in June approached, word came down from NRRI that the torrefaction reactor they were installing was behind schedule. Never to disappoint, NRRI scrambled and located another torrefaction company to supply the required fuel for testing.

Given the short notice, the torrefied biomass fuel New Biomass Energy generously donated to CSR was delivered in traditional fuel pellet size as opposed to larger, coal-lump size as planned. CSR was able to work with the Zoo to modify the grates with stainless steel mesh and spacer pieces to permit air flow while preventing the small pellets from falling between the 3/4 inch pinholes of the grates on No. 1924. 

“We instrumented the locomotive with four, Inconel-sheathed thermocouples to gauge firebed, combustion space, and exhaust gas temperatures when burning coal vs biocoal,” explained CSR Senior Mechanical Engineer Wolf Fengler. “Tests were run on Saturday and Sunday, with trains Saturday burning coal and the first runs of Sunday burning biocoal.” 

The modified grates and ends of the thermocouples can be seen in the accompanying photo. When testing, CSR burned both coal and biocoal on the modified grates as an experimental control.

“We used National Instruments hardware in concert with its LabView software to record second-by-second temperature data from the sensors,” said CSR President Davidson Ward. “Perhaps most exciting was the fact that three of the sensors were directly in the firebox, one submerged in the firebed and two at varying heights above, which provided insight into the combustion behaviors of each fuel.”

The initial results of the June tests indicated that the torrefied biomass had sufficient energy density and combustion characteristics to make steam, but we had concerns that the small pellet size was contributing to inefficient combustion. Since the small pieces packed together tightly and required many layers to build a sufficient firebed, we hypothesized that larger fuel pellets would generate equal heat with less smoke. 

Keep in mind that, to build a firebed 3-3/4” deep with 3/8 inch diameter pellets requires at least ten fuel particles, whereas the same firebed depth with 1-1/4” particles requires just three pieces of fuel. With fewer pieces, there is a larger proportional area and simpler path for combustion air to flow between the fuel, thus aiding combustion.

Testing Round Two

Following the first set of tests, we circled back with NRRI to plan a second round.
As summer turned to fall, NRRI was making steady progress commissioning its large torrefaction reactor that, at full capacity, can produce 28,000 pounds of torrefied material per day. In early October, NRRI let us know it had more than 1,000 pounds of raw torrefied biomass on the ground ready to be densified and that they should be able to amalgamate it for a late October test.

Larger, "stoker coal-sized" torrefied biomass pellets. NRRI Photo

We reached back out to Ristow and his colleagues at the Zoo to see whether a test in late October would be possible. With little delay, we received approval for the second round of testing.

Graduate students and NRRI staff researcher Tim Hagen worked diligently to densify the test material, despite lacking ideal densification binder.  Given the timelines, NRRI opted to proceed with the densification using material it had available to enable the next round of testing. The data that could be received from this round of testing would be quite helpful in informing future densification trials.

Loading barrels of fuel for shipment to Milwaukee. NRRI Photo

CSR President Davidson Ward drove to Coleraine, Minn., to pick up two barrels full of torrefied biomass pellets on the morning of Thursday, October 27. By that evening, he and the pellets were pulling into Milwaukee. To prevent large embers from leaving No. 1924, an engine that lacks both a firebox arch and a master mechanics’ front end, CSR’s Rob Mangels fabricated a spark arresting netting arrangement similar to that employed by the Colorado narrow gauge railroads.

We got to work that Friday, re-equipping the locomotive with thermocouple sensors and test-firing the engine on some of the torrefied biomass fuel. The pellets provided by NRRI were cylinders of approximately 1-1/4 x 2 inches, incidentally the same size as the stoker coal used by the Zoo to run its locomotives.

As shown at in the adjacent photo, the cylindrical pellets were relatively easy to crush, a result of the binder used in densification. By comparison, other pellets on hand densified with different binders were nearly impossible to crush, even with a hammer.

Upon the very first fireup, it became apparent that the torrefied biomass fuel burned much cleaner than coal , and that the larger biofuel pellets permitted a thicker firebed with little-to-no visible smoke as compared with the tests in June. Even when stoking the fire with many scoops of torrefied biomass at one time, the smokestack seldom showed more than a translucent gray haze.

On Saturday morning, we arrived early to fire up test locomotive No. 1924 on the torrefied biomass fuel. After about an hour of stoking, the boiler pressure gauge read just shy of 200 psi, and we were ready to begin operating trains.

With Ken Ristow at the throttle, the 4-6-2 gently  pulled its train downgrade out of the shop and through the tunnel beneath Interstate Highway 94. With the entire train in the tunnel and at the base of an approximate 3% upgrade, Ristow hauled back on the throttle, agitating the torrefied fire unlike it had yet to experience. 

The strong draft, combined with a dormant firebed, resulted in ash and cinders being blasted out of the stack. The engine roared upgrade with its 10 car test train in tow and, once the initial firebed cleaned, the stack went from hazy to clear.

Once at the top of the grade and onto the Zoo mainline, the train stopped to allow crew members to throw the switch. We then began three laps of continuous running to see how the fuel reacted in a “mainline” situation. 

With 22” driving wheels and a loop of track approximately one and one-tenth of a mile in length, the tests were undertaken over a “scale” distance of 10 miles of railroad and a top scale speed of approximately 40 miles per hour. With the biofuel tests were completed, we switched the locomotive from torrefied biomass to coal and ran the balance of the normal trains using coal, logging comparative temperature data.

Results

The results of both biocoal/coal comparison tests, one in June with small pellets and one in October with large pellets, are shown below. It is interesting to note the difference in maximum temperatures between the tests, a function most likely of the difference in grates and the impact they had on the coal firebed. Both graphs represent data recorded on two runs and synced them up, shifting the data along the “x-axis” to relate to similar segments of the railroad. Click on the graphs to enlarge.

It is interesting to note that the torrefied biomass fuel is quicker to ignite than coal and, similarly, that it is quicker to fall off in temperature than coal. This is particularly evident when comparing the findings of the October tests, wherein fuel of analogous sizes were burned. 

Given the differences in the energy content and bulk density of the fuels, these are logical results. Since the torrefied biomass pellets were of lower bulk density and of higher porosity, the increased surface area enables them to ignite quicker. The lower bulk density also means that the fuel reacts and burns quicker, resulting in a more rapid drop-off in temperature. That said, torrefied biomass burned with similar heat across the board, but the peak coal temperature was approximately 100 degrees hotter than the torrefied biomass.

Image from June showing combustion with thinner, small-pellet fire.

Image from October showing more even combustion from thicker, large-pellet fire.

The foregoing combined with the lack of ideal densification binder on the October tests resulted in the fuel tending to break apart prematurely when combusted, leading to fuel particles becoming entrained in the exhaust stream. 

We will be working closely with researchers at NRRI over the winter to develop additional blends of densified torrefied biomass for use on the next series of fuel tests at the Zoo first thing in the Spring of 2017. 

Next Steps - Transition to Standard Gauge

This stunning photo by Oren B. Helbok provides a great broad view of Everett Railroad No. 11. The railroad has offered CSR use of No. 11 for standard gauge fuel tests in 2017.

“The ability to test this alternative fuel is exciting for us; we all must find new and modern ways to help keep historic railroading alive for generations to come”

— Z. Hall, Everett Railroad Steam Foreman

If the next round of tests at the Zoo continue to progress as the past ones, we will be ready to take the torrefied fuel research from the “test scale” at the Zoo to the “pilot scale.” This will be made possible in part through the generosity of the Hollidaysburg, Pennsylvania-based Everett Railroad (EVRR).

The EVRR operates a 1923-built 2-6-0 steam locomotive No. 11, hauling excursion trains through scenic rural Pennsylvania. The management and operations department is excited about the possibility of using torrefied fuel, and they approached CSR about the opportunity.

“We are facing a growing issue of finding a reliable source of high-quality coal that meets our specs and also is low smoke; large amounts of visible smoke is something that we must be very mindful of in the areas we operate,” said EVRR Steam Foreman Zach Hall. “The ability to test this alternative fuel is exciting for us; we all must find new and modern ways to help keep historic railroading alive for generations to come.”

According to Trains magazine, there are approximately 150 coal-fired steam locomotives in operation in the U.S. today, but changing economic and environmental conditions are making the procurement of coal ever more difficult. 

EVRR fireman Stephen Lane shovels a scoop of coal into the firebox of No. 11 during a trip in December 2015. Photo by, and used courtesy of, Oren B. Helbok.

The U.S. has seen a huge decline in coal production, and it does not take much imagination to see a situation where the U.S. may also need to look at importing coal to fire steam locomotives, or even be forced to convert steam engines to oil and lose the art of hand firing. 

Even in Great Britain, birthplace of the iron horse and bastion of steam preservation world-wide, news sources including the Telegraph and the BBC have been reporting such headlines as: “Coal crisis hits steam trains” and “Coal shortage hits Vintage Trains and Severn Valley Railway.”

Thanks to the generosity of EVRR President Alan Maples, the railroad has offered to allow CSR to test fuel on No. 11 over three days in the coming operating season, an in-kind contribution of $9,000 towards this fuel research. 

CSR seeks to raise an additional $27,000 to cover the costs of  fuel densification studies this winter, an additional round of tests at the Milwaukee County Zoo in the Spring, as well as fund the manufacture of approximately 10 tons of torrefied fuel for use by the EVRR on tests with No. 11. 

Can we count on your support as we work to keep steam alive?

We strive to keep this history alive, and our Team is confident that, with the support of many, CSR can help ensure a bright future for steam in generations to come. 

Already, this important fuel research has been supported by the outstanding assistance of the Milwaukee County Zoo, the Natural Resources Research Institute, New Biomass Energy, the American Boiler Manufacturers Association, and the support of CSR’s donors, including generous contributions by Bon French and Fred Gullette. Additional research into the conversion of used railroad ties into torrefied biomass was also underwritten through generous contributions of the Indiana Rail Road. Will you help make this research a reality?

More details on densification research, additional small scale tests, and the planned full scale test will be made known in the coming months!

Biofuel Tests at Zoo - Round Two

Test locomotive No. 1924 blasts up the 3% grade hauling a heavy train. The locomotive is being fired with 100% torrefied biomass fuel and is instrumented with test equipment to gauge firebed and smokebox temperatures.

CSR and NRRI again collaborated with the Milwaukee County Zoo to undertake a comparative test of torrefied biomass fuel and coal this past October. The previous round of tests CSR undertook in June employed very small (3/8 inch diameter) cylindrical fuel pellets. While the finding of those tests were promising, CSR sought to undertake tests with fuel analogous in size to that employed on preserved steam locomotives.

The researchers at the Natural Resources Research Institute (NRRI) produced 500 lbs of torrefied biomass with its recently-commissioned torrefaction reactor and densified it using a B-100 cylindrical densifier to an approximate size of 1-1/4 x 2 inches [shown below, second from left]. These larger pieces of fuel were more analogous to the coal typically used by the Milwaukee County Zoo. As expected, the larger torrefied biomass pieces burned more cleanly in the firebox than the smaller pieces used in the previous round of testing.

As with the previous tests, CSR instrumented the locomotive with four thermocouples [shown at right], three in the firebox and one in the smokebox, to document temperatures on comparative tests between torrefied biomass combustion and coal combustion. To minimize the risk of sparks from coal/torrefied biomass fines, CSR also fabricated and installed a custom spark arrestor for use on the stack of the engine.

Tests revealed that the torrefied biomass burned with similar temperatures as the coal and with little smoke [see images at bottom]. It also revealed that the fuel has a very low ash content compared with coal.

That said, densification of the torrefied fuel still needs refinement to permit the fuel to burn more similar to coal, including for the same duration as coal per unit fired. The less dense torrefied fuel resulted in a quicker dropoff of firebox temperatures when the throttle of the locomotive was closed. These tests provided CSR with much needed data on the characteristics of torrefied biomass combustion in locomotive-style boilers, and it has provided focus for research this winter.

The cooperation of the Milwaukee County Zoo has been second-to-none in undertaking these tests, and it has provided CSR with a very good platform to undertake research. Whereas running tests in a full-size locomotive would take thousands of pounds of fuel, the Milwaukee County Zoo locomotive No. 1924 can operate a full day on 500 lbs of fuel or less. This keeps costs low in developing various fuel typologies (wood stock varieties, densification types, etc.), while still having a one third scale engine on which to test the effects of drafting and combustion.

With these tests completed, CSR is working with NRRI to undertake densification research over the winter. CSR will provide more information on those plans, including proposed future tests on standard gauge equipment, in the coming weeks.

In the meantime, please consider making a tax-deductible contribution to CSR to support the upcoming tests and research!

Firing up on coal, the locomotive had little difficulty making smoke.

Once switched to torrefied biomass fuel, the locomotive made almost no smoke.

Members of the CSR / Zoo research team pose in front of the two steam locomotives operated by the Zoo.

• People, from left to right: Davidson Ward [CSR]; Ken Ristow [Zoo]; Rob Mangels [CSR]; and Wolf Fengler [CSR].
• Locomotives, from left to right: 4-4-2 No. 1916, burning coal; and 4-6-2 No. 1924, burning torrefied biomass - both manufactured by Sandley Light Railway Equipment Works, Wisconsin Dells, Wisconsin.

Footage of First Torrefied Biomass-Run Train

This video shows the first run of the torrefied biomass test train on the Milwaukee County Zoo mainline, with footage of the train starting from the point the shop lead connects with the tracks and operating to the summit, approximately 1/2 mile. We have synced up the readings from the four thermocouples with the video footage, showing a second-by-second readout of combustion temperatures in the locomotive.

While watching the video, note that Zoo crew member, Ken Ristow, is hand shoveling loads of the small, torrefied biomass pellets into the firebox. The fuel pellets, which were graciously donated to CSR for these tests by New Biomass Energy, are much smaller than the coal typically used on a steam locomotive. We therefore modified the grates with stainless steel mesh to prevent the fuel from falling through the large pinholes. Due to the small size of the fuel, we could only build up a thin firebed (2" with biomass vs. 5" on coal), meaning there was less potential energy in the fire, resulting in the need to shovel more frequently than with coal. Likewise, NBE's pellets exhibited such good flowability, which is very important in stoker firing, that they were prone to slide off of the coal scoop.

CSR is working with research collaborator Natural Resources Research Institute and the Milwaukee County Zoo to schedule another round of testing later this year with larger, "puck" sized torrefied biomass briquettes to further verify the promising results produced from these initial tests. Likewise, we have been in discussion with standard gauge steam operators about performing full size tests in the future.

In all, the Milwaukee County Zoo tests were an extremely important scientific and risk mitigation step in this research. They allowed CSR the opportunity to collect comparative data on the combustion of coal vs. torrefied biomass (which will be made available in the coming months as part of a larger White Paper) and it proved that steam locomotives could make steam and operate safely using the alternative fuel. 

We could not have done these tests without the outstanding assistance of the Milwaukee County Zoo, the Natural Resources Research Institute, New Biomass Energy, the American Boiler Manufacturers Association, and the support of CSR's donors, including generous contributions by Bon French and Fred Gullette.

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If you'd like to help make the next set of tests happen, please consider: