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2 Νοε 2013 (πριν από 3 χρόνια και 5 μήνες)

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Steve Clark, PE
Arup USA
7670 Woodway Drive, Suite 162
Houston, Texas 77063
+1 713-783-2787

Saud Memon, PE
Arup USA
7670 Woodway Drive, Suite 162
Houston, Texas 77063
+1 713-783, 2787

Anthony Combs
Metropolitan Transit Authority of Harris County Texas
1601 W. Belfort
PO Box 61429
Houston, Texas 77208
+1 713-982-8213

Word Count: 2466
This paper presents an innovative method used by Metropolitan Transit Authority of Harris County
Texas (METRO) for the installation of rail lubricators along their existing Red Line. This is an
embedded track light rail line in Houston, Texas. Prior to the installation of the gage face rail
lubricators, the rails were manually lubricated several times per week. The manual lubrication required
a track person to apply the lubricant to the curve locations. This method was labor intensive and
provided a poor control of friction management.

The implementation of these state-of-the-art electro-mechanical wayside rail gage face lubricators at
the curved areas along METRO’s Red Line provides reduced risk of flange climb derailments,
improved wheel life, improved rail life on the curves, noise abatement, reduced energy consumption on
the curves, and improved rail gage retention by reduced rail wear.

The installation of gage face rail lubricators on an embedded track is particularly challenging, and
METRO was unable to find an operator or supplier who had previously performed this type of
installation in the United States. Therefore, they had to develop the installation process in-house, with
assistance from Arup (the consulting engineers) and the lubricator supplier.

The Metropolitan Transit Authority of Harris County, herein referred to as METRO, is a major public
transportation agency based in Houston, Texas. It operates bus, light rail, and para-transit services
(under the name METROLift) in the City as well as in most of Harris County. METRO’s Red Line ranks
as the eleventh most travelled light rail system in the United States, with the second highest ridership
per track mile. METRO began operating the 7.5 mile Red Line in 2004, and has an average daily
weekday ridership of 45,000 passengers.

Arup North America, Ltd. (Arup) had previously worked with METRO when Arup had analyzed a
derailment that had occurred on June 16, 2009, near South Braeswood Street along METRO’s Red
Line. Arup was asked by METRO to work alongside them in the derailment investigation and provide
an independent third party opinion pertaining to the cause of the incident as well as to make
recommendations to mitigate the potential for any future derailments at that location. Arup worked
directly with METRO during this investigative study, utilizing a combination of information gathered and
processed by METRO and Arup. The derailment investigation is relevant to the topic of this paper in
that one of the conclusions drawn in the derailment investigation was the absence of adequate rail
lubrication, although the cause of the derailment was found to be human error.

METRO thus opted for the installation of gage face rail lubricators similar to the one currently installed
at its Rail Operations Center (ROC). The ROC has ballasted track in the yard, so the difference is that
the new lubricators would be installed in embedded tracks, thus posing a unique installation challenge.
Besides the issue of dealing with an embedded track, the functionality of the lubrication system was the
same as the one at the ROC where the sensors determine the number of axles of the approaching train

and initiate the lubrication. The application of the lubricant is controlled by the number of axles applied
to the wheel sensor through the main controller box. A high pressure pump supplies the wiper bars
with a precisely metered amount of lubricant. The lubricant is picked up by the wheel flange of the train
and evenly distributed on the rail gage face for some distance past the applicator. It is anticipated that
several closely spaced consecutive curves will be supplied with lubricant from only one gage face
lubrication location. A lubricant with relatively high viscosity was selected with the idea that it will
adhere to the rails better and not leak directly into the track bed. Figure 1 below shows the photograph
of a train on the embedded track along the Red Line.

Figure 1 – South Bound Train on METRO Red Line Showing Typical Track

METRO, with the help of Arup and the lubricator supplier was able to successfully develop an
innovative installation system for the gage face rail lubricators on their existing embedded track to be
installed at eight (8) locations (a total of 9 applicators) along the Red Line. Four (4) of these applicators
are on the North Bound (NB) track and five (5) applicators are on the South Bound (SB) track. Location
number four (4) has a double applicator, one for each of the NB and SB directions.

The sketch below shows the locations along the Red Line where the gage face lubricators are proposed
to be installed. The installation is already complete at four (4) of these eight (8) locations. The
locations installed are 2, 3, 4, and 5 (depicted in Figure 2 below) with location number 4 being a double.
The installation at the remainder of the locations will be completed by the end of 2010.

Figure 2 – Proposed Locations for Rail Lubrication along Red Line

It is well known that rail lubrication increases the wheel and rail life by preventing friction and
decreasing the wear between the rail-wheel interface, saves energy, and can reduce wheel noise. It
can also reduce lateral forces and flange climb forces that can lead to flange climb derailments. The
METRO Red Line has several sharp radii curves along the Red Line between West Belfort and the IH-
45 overpass. It also passes through the Texas Medical Center District and the Houston Central
Business District, thus, the potential to reduce noise was considered beneficial.

All the equipment and typical part numbers were provided by the METRO selected supplier. Following
are the main components of a gauge face rail lubrication system which are also depicted in Figure 3
 Wheel Sensor
 Wiper Bars/ Applicators
 Solar Panel
 Lubricant Reservoir

Figure 3 – Typical Design of Rail Lubrication System

Wheel Sensor
The Wheel Sensor, as the name implies, senses the approaching train and initiates the lubrication
cycle. The sensor counts the number of axles and uses this information to determine the optimal
quantity of lubricant for the track conditions. The Wheel Sensor is protected in a vibration and weather
proof housing and mounted on the inside of the high rail. It sends a signal back to the system controller
when the train is passing.

Wiper Bar (Applicator)
The Wiper Bars dispense grease onto the gage side of the rail. The rubber-tipped wiper bar places the
grease high on the rail gage face for greater contact with the wheel flange. The grease is dispensed
evenly using a progressive metering valve that ensures an equal volume of grease to each wiper bar
port. The strategic mounting and positioning of the applicators enables a safe and reliable operation,
as well as an optimum lubricant distribution.

Solar Panel
Solar Panels charge the system. Solar panels are installed such that they receive sufficient sunlight
throughout the day and are not blocked by trees or structures. Furthermore, special consideration is
given to the positioning of the solar panel to ascertain that these panels don’t reflect a glare at the train
driver, or interfere with their line of sight.

The reservoir consists of two electric pumps, a grease pan and controller box. Located inside the
reservoir, the controller is set to pump once a pre-determined number of axles pass by, thereby
controlling how long the pump ought to run. Various controllers are available depending on the
requirements; however a manual controller with dial knobs was selected for the subject solar powered

The following steps were taken to complete the design of the eight (8) locations and installation of the
initial four (4) locations:
 Site Location
 Design Development
 Installation
 Selection of Lubricant and Grease

Site Location
The number of lubricators needed and their spacing along a particular track route, depended on several
factors. These factors included but were not limited to the curve radius, track grade, train speed, and
braking requirements. These factors influenced the retention and carry distance of the grease. Care
was taken for the lubricators to be installed on a length of tangent track near an easily accessible level.

The location for the reservoir assembly was selected such that it was outside both the NB and SB train
catenary and that the reservoir assembly and solar panel were placed in the middle of the two tracks.
Moreover, since the unit was powered by a solar panel, therefore special consideration was given to
ensure that there was uninterrupted access to sunlight for most of the day. The photograph below
shows the embedded track before the installation of the rail lubrication system at Braeswood (Location
Number 4) where wiper bars were installed for both the NB and the SB track:

Figure 4 – Track before the Installation of Rail Lubrication System

Design Development
After finalizing the locations for the lubrication system, Arup prepared detailed drawings to show the
proposed location of the reservoirs, solar panels, wheel sensor and wiper bars. The design drawings
showed the location of each reservoir with reference to the poles carrying the overhead contact system
wires and their respective stations. Typical sections showing the detail design of the base slab, saw cut
locations and drill locations for the conduits and feed line were prepared. After detailed deliberation
and design consideration the consensus was to saw cut and drill the concrete along and beneath the
track and subsequently lay the conduit from the reservoir to the wiper bars.

Arup, the supply contractor, the general contractor, and METRO conducted a pre-installation site review
of the proposed lubricator system locations to mark the areas. After verifying and marking the locations
on the site, the contractor was given the notice to proceed with the installation of the lubrication

A unique challenge in the installation was the limited window of opportunity within which this task
needed to be accomplished. A 36-hour window of opportunity starting from Friday night and ending on
Sunday morning was allotted by METRO where the service could be suspended on this line for the
installation of the proposed lubrication system. Consequently, the focus was upon the rail-mounted
equipment installation, with the reservoirs being installed at later date.

The following are some of the main challenges, points of interest, and highlights of the installation:
 Out of the initial four locations, the installation of the lubrication system was initiated at the
double applicator track at Braeswood (Location Number 4). The concrete was saw cut and
then open drilled for the wiper bars and wheel sensor. The existing rubber boot along the rail
was cut to make room for the wiper bar and wheel sensor. The photographs below show the
saw cut, concrete drilling and the cutting of the boot.

Figure 5 – Saw Cutting of the Concrete

Figure 6 – Drilling of Concrete for the Wiper Bar and Conduit Installations

Figure 7 – Cutting of Rubber Boot at Wiper Bar Locations

 The wiper bar was installed such that it was flush with the rail and clamped to the ground so
that its movement would be minimal. The gage face wiper bar was attached to the gage side
of the rail and secured with two clamps. The photographs below show the clamp connection
and the wiper bar installation:

Figure 8 – Wiper Bar Assembly Mounted to Existing Concrete

 A 2-inch PVC pipe schedule 40 conduit was installed to carry the grease hose and the feed
line from the wiper bars to the reservoir. The grease feed conduit was attached to a metering
valve that would evenly dispense the grease to the ports. The following photograph depicts
the conduit containing the grease hose and feed line:

Figure 9 – PVC Conduit Carrying the Grease Hose and Feed Line

 The solar panel and the reservoir base were installed such that they had enough clearance
from the rail traffic and were outside the train’s catenary envelope. The solar panel was
erected on a 4-inch galvanized iron pole and the direction of the solar panel was selected not
only such that it would receive ample sunlight throughout the day but also in a manner that
the solar panels would not cast a glare onto or be in the line of sight of the train driver. The
reservoir bases and the solar panel base were installed on 6-inch thick concrete slabs to
protect them from storm water runoff and provide a stable base. A visual of this can be seen
in the photograph below:

Figure 10 – Solar Panel and Reservoir Base before Pouring of Concrete and/or Iso Flex

 Iso-flex, a non-conductive boot repair polymer, was used for filler around the rail-mounted
components. Iso-flex is a three part polymer with the first two parts supplied by the vendor
and the third part, being Sand, added before installation to strengthen the compound as
shown in the photographs below:

Figure 11 – Iso Flex Compound Mixture Preparation

Figure 12 – Pouring the Iso-Flex Compound at the Wiper Bar Locations

The figure below shows the photograph of a finished system depicting the lubricator wiper bars, wheel
sensor and reservoir pad at Braeswood. Reservoirs had not yet been installed at the time of this paper.

Figure 13 – Installation of Wiper Bars, Wheel Sensor and Reservoir Pad along the Red Line

Selection of Lubricant and Grease
METRO uses a preferred brand of lithium based grease that is biodegradable and ecologically and
environmentally friendly. An environmental and safety review was completed by METRO prior to the
installation of this lubrication system. The review concluded that there were no environmental impacts
at the locations.

List of Tables and Figures
Figure 1 – South Bound Train on Embedded Track
Figure 2 – Proposed Locations for Rail Lubrication along Red Line
Figure 3 – Typical Design of Rail Lubrication System
Figure 4 – Embedded Track before the Installation of Rail Lubrication System
Figure 5 – Saw Cutting of the Concrete
Figure 6 – Drilling of Concrete for the Wiper Bars and Conduit
Figure 7 – Rubber Boot Cutting at Wiper Bar Locations
Figure 8 – Wiper Bar Assembly Clapped to Existing Concrete
Figure 9 – PVC Conduit Carrying the Grease Hose & Feed Line
Figure 10 – Solar Panel and Reservoir Base before Pouring of Concrete and/or Iso Flex
Figure 11 – Iso Flex Compound Mixture Preparation
Figure 12 – Pouring of Iso Flex Compound at the Wiper Bar Locations
Figure 13 – Typical Installation of Wiper Bars, Conduit, and Reservoir Pad along the Red Line