BALLAST CLEANING TO IMPROVE DRAINAGE IN METROLINK’S … · Memories of previous events caused a great deal of concern for Metrolink Engineering Management and preparations were

BALLAST CLEANING TO IMPROVE DRAINAGE IN METROLINK’S VALLEY SUBDIVISION TUNNEL 25

Tim Harris

Track Maintenance Engineer 2704 North Garey Ave.

Pomona, CA 91767 213/494-1215

[email protected]

Number of Words: 3,527 ABSTRACT The predictions for a “Godzilla” El Nino storm event in the winter of 2015/2016 preparations were made to improve the drainage in Tunnel 25 on the Valley Subdivision. The tunnel has water flow and as a result the ballast in the tunnel had become fouled and the saturated condition of the ballast was causing a rapid deterioration of ties. The tunnel is 6,976 feet long and is sloped 0.63% from the East to the West end. Train traffic through the tunnel on a weekday includes 30 Metrolink commuter trains, two Union Pacific (UP) Intermodal, one UP local freight (out and back), and one UP Rock train (out and back). On weekends the number of trains is reduced with 12 Metrolink commuter trains, the same number of UP trains on Saturday but none on Sunday. This made scheduling work windows for the work a challenge. This work was done using four hour work windows on Saturday night and 25 hour work windows on Sundays for seven weeks with one 54 hour work window during the entire weekend of January 9th and 10th. The work was begun December 12, 2015 and continued for eight weeks being completed January 31, 2016. Metrolink maintenance contractor VTMI procured the services of a Loram RailVac™ train which was used to remove ballast from the tunnel. When completed the project accomplished the removal of approximately 3,690 yd3 of old ballast and the replacement with new ballast and the installation of 988 new ties. PROJECT BACKGROUND Starting in early 2015 predictions for a massive “Godzilla” El Nino storm event starting to be predicted. Memories of previous events caused a great deal of concern for Metrolink Engineering Management and preparations were discussed about how to prepare to deal with these storms. Tunnel 25 is on Metrolink’s Valley Subdivision is located about 26 miles from Union Station (downtown Los Angeles) on the far North side of the city of Los Angeles. It is located at the Newhall Pass which is a major transportation point between the San Fernando Valley and points North. The Southern Pacific constructed the tunnel and the bore was first completed July 14, 1876 and trains began operating through the tunnel on August 12, 1876. This route was the first rail line competed between Los Angeles and San Francisco. The Los Angeles County Transportation Commission acquired the rail line and structures including the tunnel in 1992 and the Southern California Regional Rail Authority (Metrolink) maintains the structure.

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The Metrolink Engineering Management staff began formulating a plan for how to prepare for the upcoming El Nino storm event which included preparing Tunnel 25 so that it could handle expected additional water drainage into the tunnel and removal of the water from the tunnel around the track. The tunnel had last seen a major maintenance program in 2006 where new ties and rail had been placed. Since that time the tunnel had seen periodic maintenance which included surfacing. The surfacing had added ballast in the tunnel and the excess ballast had been pushed up against the tunnel walls so that in some places the ballast was at the rail head level. The tunnel is 18 feet wide so the raised ballast was well away from the end of the ties but needed to be removed. PROJECT PLANNING Before the project could begin an estimate of how much the project would cost had to be developed so that sufficient funding could be sought to do the project. Six different scenarios were examined and costs for each of these was estimated. The scenarios varied by how much ballast would be removed by depth, just removing ballast to the edge of ties, or to just remove ballast at the locations that water was present in the track structure. These scenarios varied in cost from $600,000 to $1,200,000. From this information a choice was then made by Metrolink Engineering Staff that the tunnel ballast would be removed and replaced and the ballast would be removed to just below the ties from tunnel wall to tunnel wall. In 2006 an examination of the tunnel floor had been performed and the depth of the tunnel floor had been determined by core drillings. From this data a diagram of the depth of the ballast was developed and is shown in Figure 1 below. While this data was old the approximation of the profile of the tunnel floor was used to assist in the development of the estimate of the project cost. In addition prior to the start of the tunnel work a hi-rail trip through the tunnel was done and a video of the existing condition of the tunnel roadbed was created. This video was then used and the locations of wet spots in the tunnel roadbed was documented. This information was then added to the tunnel floor diagram shown in Figure 1. One could see that there was a correlation between the location of the wet spots and locations where the ballast section was thin.

Figure 1 Tunnel 25 floor characteristics showing the approximate depth of ballast and the locations of wet spots in the tunnel roadbed.

Locations in the tunnel were referenced using the pump system that had been installed in the tunnel to better drain the water that infiltrates into the tunnel. These pumps are located along the North wall of the tunnel at 100 foot intervals. Work locations throughout the project were referenced to pump locations.

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WORK PLAN A preliminary budget was prepared based on funding availability. This budget included funding from the Los Angeles Metropolitan Transit Authority, Caltrans, and the Federal Transit Administration. The initial budget was $880,000. As stated previously a preliminary estimate of the cost of the work based on removing the existing ballast to the base of the ties from tunnel wall to tunnel wall had been determined. This would give an approximate removal of 2/3 yd3 per track foot. So it was estimated that approximately 4,700 yd3 of ballast would need to be removed and replaced.

Figure 2 The Loram RailVac RIV17 shown in the Metrolink maintenance spur

near the East portal to Tunnel 25.

VTMI, Metrolink’s maintenance contractor, contracted with Loram Maintenance of Way for the use of the machine. Metrolink then issued a contract task order to VTMI with the scope to vacuum Tunnel 25 on the Valley Subdivision and Tunnel 26 on the Ventura Subdivision (work was done over three weekends following the work at Tunnel 25). The Loram RailVac used for this operation is shown in Figure 3 above. Once a general plan for the work at Tunnel 25 had been developed VTMI and Metrolink engineering staff met with the Metrolink Dispatch staff and a plan was developed for working in the tunnel. It was determined that service on the Valley Subdivision would be halted between the Sylmar/San Fernando Station East of the tunnel and at the Newhall Station West of the tunnel. Passengers would then be bussed between these two stations while the work in the tunnel was being done. Service on the Valley Subdivision on Sundays had a total of eight trains operating between Los Angeles Union Station and the Lancaster commuter rail station. Prior to starting the tunnel vacuuming project some effort had been made to replace some of the ties in the tunnel. This had been going on since mid-November 2015. This work had been done starting early Sunday morning and continue until early Monday morning when Metrolink service would resume on the Valley Subdivision. Before the RailVac was used the average number of ties that were changed on a

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weekend was 25. It was determined that this work would be continued while the RailVac worked which allowed for a significant increase in the number of ties that were replaced during the work window. The tie replacement cost was done under the maintenance budget for the line segment that included Tunnel 25 so these costs are not reflected in the work budget for the RailVac. The cost of the replacement ballast was also included in the Maintenance budget.

Figure 3 Tunnel chart from January 9, 2015 showing sections of tunnel that had been vacuumed and sections that will be done in the future.

As the work progressed charts were done on a weekly basis to monitor the work schedule and to present to Metrolink Engineering and Staff. One of these charts is shown in Figure 3 above which shows a diagram of the work that had been done and what was planned in the following work windows. The chart gave a more graphic representation of what had and would be done. The Figure 3 shows the work that had been done prior to the January 9th weekend. The West third of the tunnel had been completed and a short section on the East end and about 300 feet outside the tunnel had been completed. While the work was being done it was realized that the progress being made in the available work windows would not allow us to finish vacuuming the entire length of the tunnel and that we would have to reduce the scope of the work and exclude portions of the tunnel and thus had to determine where to focus our efforts in the remaining time. But instead after the shortfall was realized Metrolink management made a decision to increase the work time available to complete this work. So during the first week of January it was determined that an additional full weekend work window (54 hours) on the weekend of January 9th and 10th would be done in

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order to add time so that the vacuuming of the entire tunnel could be finished by the time the weekend work windows ended. This decision allowed for the ballast around the track to be removed for the entire length of the tunnel in the available time. HOW THE WORK ACTUALLY HAPPENED The schedule for most of the weekends the RailVac worked would have the work start late Saturday night, early Sunday morning the work window would begin with the passing of the Union Pacific intermodal Z train headed to Seattle from the Los Angeles Transportation Center near downtown LA. The train would pass at 2 A.M. and continue until 4:00 A.M. Monday morning. A VTMI track inspector would then take the track through the tunnel out of service. Once the track was out of service the Track Inspector would take a hi-rail vehicle into the tunnel and lead the RailVac to the location where the RailVac would start working. The RailVac crew would be prepared to move as soon as the track became available. The Metrolink Brandt truck and air dump car would be coupled to the RailVac as it moved into the tunnel. Once inside the tunnel the RailVac would start working by vacuuming ballast along one side of the tunnel for about 100 feet removing ballast from the tunnel wall to the end of the tie, then work back to where it started working vacuuming ballast from the opposite side of the tunnel. Once the ballast from both sides of the tunnel had been removed the RailVac would then begin removing the ballast from the cribs of the track. On average the RailVac could remove the ballast from tunnel wall to tunnel wall down to the base of the ties in about an hour and a half per 100 feet. Early on it was discovered that the ballast in the tunnel was so wet that on some occasions it would not be able to be conveyed out of the RailVac into the air dump car. The wetness of the ballast is shown in Figure 4 below which shows the water that in some of the removed ballast and Figure 5 showing the amount of water that was moving to a nearby pump. The ballast would move best if it was dryer. The work had started with the RailVac removing the ballast from the entire width of the tunnel. As we gained experience in the best way to remove the ballast we found that using the short work windows during the weekdays. These windows were about four hours during which the RailVac would go into tunnel and vacuum along the North side tunnel wall cutting a trench to allow the ballast to drain towards the pumps. This allowed the ballast to dry so that it would mover more easily in the RailVac conveyor system and be loaded into air dump car for removal from the tunnel. The technique developed overcome this was to use existing shorter work windows between trains during weekdays to create greater drainage in the roadbed in the tunnel. There is a period of about seven hours between Metrolink commuter trains. There are two Union Pacific trains that would operate in this time and the RailVac would be moved back into the Maintenance siding to clear for these trains. During the work time the RailVac would clear a trench along the tunnel wall and clear individual cribs at locations where water was collecting to allow the water to drain to the pumps.

After this pattern of operation had been developed the RailVac was able to vacuum from 800 to 1000 feet during the long Sunday work windows.

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Figure 4 A ballast load being dumped on the Maintenance Spur near the East end of the tunnel.

Figure 5 A cleared ballast along the pump side tunnel wall allowing drainage to the pump system.

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Figure 6 below shows the RailVac working to remove ballast along one of the tunnel walls. Figure 7 shows a section of track inside the tunnel that the ballast had been removed from.

Figure 6 the RailVac working removing ballast along the tunnel wall.

Figure 7 Showing the track after it has been vacuumed by the RailVac. All fouled ballast has been

removed. You can also see how wet the ballast was by seeing the excess water on the right side along the tunnel wall.

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When the track had been cleared of ballast and the RailVac cleared from the tunnel early Monday morning fresh ballast would be brought in from where it was staged at a small siding on the West side of the tunnel. The ballast was placed into the track and during the end of the work window the surfacing crew would dress and surface the track before the first train on Monday morning. As the track speed in the tunnel was 30 mph no speed restrictions were necessary so that no train delays were caused by the work in the tunnel. The RailVac has a storage capacity of about 40 yds3 after which it would need to be unloaded. As the RailVac would fill it would be unloaded while it was working or stop work and just unload until the air dump car was filled. It was found that due to the restricted air flow in the tunnel that it would work better to stop work and unload the RailVac. As stated earlier in order to allow the RailVac to work continuously a Brandt truck and air dump car were used to take ballast that had been removed from the track structure to a location where it could be disposed of. As shown in Figures 9 and 10 below the location where this work was occurring is rather restricted as to available space and the work crew disposed of the old ballast along the right of way. Once the air dump car was loaded it would be moved out of the tunnel onto a maintenance spur near the East portal of the tunnel. The air dump car would be moved by the Brandt truck to the far end of the maintenance spur where it would be dumped. A loader would then move the spoils to locations along the right of way. The ballast spoils were located along a hillside clear of the track.

Figure 8 the air dump car being unloaded at the maintenance spur.

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Figure 9 maintenance spur where the work equipment was stored when work was not being done. The spoils for the work were moved to along the slope on the left side of the track in the far distance.

Figure 10 A view showing the location of the track and the maintenance spur on the left side center of this picture. Some of the spoils can be seen in the center of this Google Earth map along the roadway above

the track.

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TIE REPLACEMENT WORK The removal of the fouled ballast and the long work windows allowed an opportunity for the replacement of ties in the tunnel. Figure 11 below shows a chart that was prepared in October 2015 giving the number of ties and their approximate location in the tunnel that needed to be replaced. Figure 12 shows a tie gang working to remove and replace a tie at the West portal of Tunnel 25. The RailVac had worked previously to remove the ballast at this location which allowed for a quicker change out of the tie. Figure 13 shows some of the removed ties at the same location. The old ties were stockpiled here and then removed during periods of no train service during the week. Prior to the RailVac working in the tunnel it was necessary for a minimum of a cluster of five ties be replaced. This was done to allow room for the ties to be removed and inserted in the confines of the tunnel. As was stated earlier prior to the RailVac working the work group was able to replace about 25 ties per weekend. This method of changing ties had been done for three weekends prior to the RailVac starting to work in the tunnel. Once the RailVac began working to clear ballast the number of ties that could be inserted increased to around 100 ties per weekend. By the time the RailVac finished working in Tunnel 25 988 ties had been replaced. This is the number of ties that were changed in three weekends of work without the RailVac and nine weekends of work with the RailVac.

Figure 11 A chart showing the location of needed replacement ties in Tunnel 25

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Figure 12 A track work group removing an old tie at the West portal of Tunnel 25. This area had been

cleared by the RailVac which made the removal of the old tie and insertion of a new tie easier.

Figure 13 Old ties that had been removed for replacement at the West portal of Tunnel 25.

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Figure 14 Diagram showing locations where tunnel had been vacuumed and how many ties had been

replaced.

Figure 15 showing the roadbed with new ballast and the drainage channels on each side of the tunnel.

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CONCLUSION The El Nino event that was predicted did not create as much rain as was first expected (only 10 inches of rain fell in January and February in the area) but the work that was planned to prepare for the event helped to put the condition of the track in Tunnel 25 in a much better condition. The use of the RailVac greatly expedited the work that could be done in tunnel 25. Given the constraints caused by the rail traffic and the conditions at the tunnel we were able to achieve a great deal. We were able to improve the condition of the roadbed and track structure in the tunnel to the point that three to five years of additional service life of these items is expected. The work done during these two months achieved the removal and replacement of approximately 3,700 yd3 of ballast and the replacement of 988 ties in the tunnel. The removal and re-profiling of the ballast roadbed in the tunnel and the removal of the excess ballast along the tunnel walls have improved the drainage in the tunnel so that the tunnel if fully ready to deal with the water flowing into the tunnel either by normal or storm caused drainage into the tunnel. The work done by the Metrolink Engineering Staff, maintenance contractor VTMI, and Loram Maintenance of Way did a tremendous job in undertaking this project and have achieved a tremendous goal to maintain this facility so that it can continue to provide service for the commuting public in the Los Angeles region.

AUTHOR BIOGRAPHICAL SKETCH

Tim Harris is a track maintenance engineer with the Southern California Regional Rail Authority (Metrolink), a position he has held for 5 years. Tim joined Metrolink after 5 years with the New Mexico Department of Transportation, where he served as a bridge engineer, a rail planner and finally as the Rail Manager while the New Mexico Rail Runner Express commuter train was being constructed. Tim has his B.S. in Civil Engineering from California State University, Los Angeles and an M.S. in Engineering Management from Cal State Northridge and is a registered engineer in the State of California. Tim lives with his wife in Altadena, California. He is currently a member of AREMA Committees 11 and 30.

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