Boise Locomotive Operations
By Dennis L. Nott
In early 1992, the Boise Locomotive Company (formerly
Rail Corporation) perceived a need for development of a new, highly
switcher locomotive as a replacement for North America's aging
fleet. Paramount in the decision to develop a new switcher
was the desire to incorporate state of the art control systems for
tractive effort, economical operation and maintenance and superior
performance. To this end Boise Locomotive Company formed a
alliance with Caterpillar, Inc., to design and produce North America's
first microprocessor controlled 1,200 HP locomotive fueled entirely by
liquefied natural gas (LNG), the MK1200G.
In 1993 the Boise Locomotive Company was approached by the Union
Railroad (UP) and the Atchison, Topeka and Santa Fe Railway (now part
the Burlington Northern Santa Fe, BNSF) to produce two MKI200G
for each company for use by each railroad as an LNG demonstration
in the Los Angeles Basin. This resulted in the delivery of
UP 1298 and LTP 1299 to the Union Pacific in August of 1994 and ATSF
and ATSF 1201 to the Burlington Northern Santa Fe in December of
The Union Pacific 1200Gs went into service on September 22, 1994 and
ATSF 1200Gs on December 5, 1994.
The Boise Locomotive Company has designed several
operational and safety
improvements over existing switchers in the new MK1200G switchers
The Caterpillar G3516 spark ignited, turbocharged - aftercooled (SITA)
LNG fueled V- 16 engine that produces the lowest NOx emissions of any
of its class.
Modern electrical rotating equipment, including electric motor drive
for the air compressor, supplied by KATO Engineering, a division of
A Boise Locomotive Company designed state-of-the-art microprocessor
locomotive control system for superior traction and engine
An advanced LNG fuel management system of cryogenic tanks, process
piping, vaporizer and controls designed by Minnesota Valley Engineering
A modern, high visibility ergonomically designed cab.
Excellent collision protection for short, nose end of locomotive.
Six-row mechanically bonded radiator cores that remove heat from
jacket water and aftercooler circuits that are cooled by two 48-inch
driven cooling fans.
Two axle Blomberg type trucks with 40 inch wheels, G-G type
bearings, 62:15 gear ratio, and clasp composition brakes providing
ride, tracking and braking.
(Slide general arrangement)
AAR Designation B-B Industry designation 0440
Nominal dimensions and capacities are as follows:
Length, coupler to coupler 56 ft. 2 in.
Length between bolster centers 31 ft. 0 in.
Weight, loaded 236,000 lbs.
Fuel capacity, LNG 1,400 gals.
Sand capacity 50 cu. ft,
Cooling water capacity 190 gals.
Lube oil capacity 219 gals.
Minimum curve coupled to
Minimum curve coupled to locomotive 274 ft,
Traction motors 4
Type DC, series wound, axle hung
Gear ratio 62:15
Wheels 40 in.
(Slide tractive effort)
Performance data is as follows:
Engine RPM 1,500
Traction HP 1,200
Maximum speed 70 MPH
Minimum continuous speed 6.2 MPH
Minimum continuous tractive effort 60,000 lbs.
The Caterpillar G3516 SITA engine is a mature design natural gas engine
used in thousands of applications throughout the world, but their
use has been in the stationary generating plant application. The
application of the G3516 SITA engine to the MK1200G locomotive is the
time this engine was used in a locomotive, or a variable load
Caterpillar took two years to enhance the design of the engine to meet
the demands of this application.
The basic engine features are:
16 cylinder - 60oV configuration
Turbocharged - aftercooled
4 - stroke cycle
11.1 compression ratio
1,350 BHP @ 1,500 rpm
Low firing pressures
170 mm bore and 190 mm stroke
2 - intake and 2 - exhaust valves per cylinder
Electronic ignition system (EIS)
Air/fuel ratio control
Fast transient response
Trouble shooting and maintenance capabilities
The G3516 SITA engine is unique from diesel counterparts
the low pressure LNG gas delivery system and spark ignition
The G3516 uses low-pressure (40-psi) gas flow out of the initial Acme
regulator. The gas then flows to the Sprauge regulator that
the gas to the engine at 6 to 8 inches of water at idle (increases with
engine speed). The gas flows to the engine through a carburetor
is spark ignited by a spark plug within the cylinder. The 1200G
on pure LNG and does not require diesel fuel to be mixed with the LNG
do high pressure (3,000 psi) direct injected systems that were tested
high horsepower locomotives in 1995 and 1996.
(Slide emissions performance)
The emissions performance of the Caterpillar G3516 SITA engine is as
ISO 8178-1 Conditions
Oxides of Nitrogen (NOx) 2.0
Carbon Monoxide (CO) 1.9
Hydrocarbons (HC) 2.8
The fuel system on the 1200G can be divided into three (3)
the fuel tanks, process piping, valves, and the LNG vaporizer.
(Fuel tank slides)
Fuel tanks of the 1200G must be cylindrical to provide the
necessary to store the fuel because LNG is a cryogenic material under
to moderate pressure when stored. The fuel storage system on the
1200G is three separate interconnected tanks with a total capacity of
gallons of LNG. There is one tank of 900 gallons in the middle of
the tank system and two outer tanks of 250 gallons each. Because
of the cylindrical design required the space normally occupied by a
fuel tank on the locomotive could not be efficiently utilized resulting
in the lower fuel capacity of the 1200G. Under normal operating
the 1,400 gallons of LNG is equivalent to about 900 gallons of diesel
on a diesel-powered switcher.
The inner shell of each tank is fabricated from 1/4-inch thick, ASTM
304 stainless steel to hold the temperature of the LNG at approximately
-260 degrees F. The inner shell is blanketed with approximately
inches of an aerospace developed insulation material and then installed
in a high strength carbon steel (ASTM A572) outer shell of 1/2 inch
that provides the tank structural integrity.
After the outer tank is capped and sealed the insulated space between
the inner and outer tanks is vacuum pumped to improve the insulating
of the system. All three tanks sit in a tank cradle that is
to the frame of the locomotive. The dynamic load capability of
fuel tank system is 10G in all directions. In addition, the
of the tank cradle is protected from derailment puncture by a steel
plate. Fuel level monitoring is accomplished with capacitance
in each of the LNG tanks.
Process piping on the system is simplified by the fact that
engine is a low-pressure engine. When the fuel tanks are fully
the saturation pressure of the LNG is 70 to 100 psi. This means that
pressure of the evaporated gas alone will provide enough gas pressure
run the engine without the use of pumps. The process piping and
fittings are Schedule 40 stainless steel and all valves on the tank
are all made of bronze because of the cryogenic nature of the
There are three separate process piping and valve systems on the
the LNG fill and off load piping; the LNG fuel tank to engine supply
and the gaseous fuel and vent pipe system (discussed later under
All piping and fittings at the end of the fuel tanks are protected by a
steel collision plate.
The final component of the fuel system is the liquid-heated
The purpose of the vaporizer is to assist the vaporization of the
LNG as the fuel supply depletes in the fuel tanks. The vaporizer
is a cylindrical liquid - to - liquid heat exchanger that uses engine
water to raise the temperature of the LNG to aid evaporation.
ROTATING ELECTRICAL SYSTEMS
(Slides rotating equipment)
The main traction alternator is a KATO 8P6.5-3000, coupled
to the engine
by a flexible coupling. AC power is rectified to the rated 1,050
VDC and 4,000 amps continuous output with an intermittent capacity of
amps. The traction alternator receives excitation from the
alternator. It is ventilated by an internal, direct drive cooling
The traction alternator is also of double bearing design to increase
The companion and auxiliary alternators are combined into
which is coupled to the engine crankshaft through a 1:1.33 gear
The companion alternator is a 130 kW, KATO series 6P2-1450
field machine equipped with slip rings and brushes. AC is output
at a rated 183 VAC, 100 Hz, 3-phase power at 2,000 RPM.
to the main field is provided by the auxiliary alternator.
The auxiliary alternator is an 18 kW KATO series 6P2-0500,
field machine. 55 VAC is rectified and output is rated at 74 VDC.
The exciter field is controlled by the voltage regulator by a VR 10
Four D78B traction motors are connected in full parallel
with no motor
or alternator transition required.
The 1200G use a MK-LOC microprocessor control system to
control, adhesion engine control, diagnostics systems and LNG gas leak
detection and control.
The excitation control system regulates the traction alternator
It is linked to the adhesion control system, which optimizes available
adhesion. Load control maintains horsepower in accordance with
locomotive's tractive effort characteristics.
The adhesion control system provides smooth, uniform wheel creep action
to maximize adhesion for any locomotive and track condition.
rotation rate signals are received from hub mounted axle
The engine control system maintains accurate engine speeds of plus
or minus 1%. Engine speeds are set to maximize fuel economy and
resonant vibrations for each throttle position. Engine control
low idle, hot engine protection and automatic fan sequencing.
The diagnostics system monitors the locomotive performance, stores
all critical information, and provides a historical fault log to
personnel for quick troubleshooting and maintenance turnaround.
system reacts to a full range of fault and trending conditions and
critical events that require operator action. The
command procedures and fault logs are stored in software, hardware, and
nonvolatile memory. If required, service information can be
on the onboard computer screen, displayed on a portable interface
or off-loaded to a remote terminal.
The 1200G also have continuously powered methane detectors that provide
input to the microprocessor control system that will activate engine
down and warning systems.
SAFETY AND CREW COMFORT
(Slide of cab)
The 1200G were designed with numerous features for crew
safety and comfort.
The cab design allows adequate room for normal crew movement within the
cab as well as space for a refrigerator and steps down to the short
if a toilet is installed there. The cab meets all AAR clean cab
The under-floor mounted HVAC system also provides the crew with a clean
and comfortable environment in which to work.
The cab was designed to provide the engineer and other crew
with excellent 360 degree visibility. The short nose of the
is lower and slopes down for larger windows could be installed.
window over the long hood of the locomotive affords the crew additional
visibility in that direction. The engineer's view is enhanced by
the raised platform that the control stand sits on.
The cab is also insulated against noise. It has excellent sound
of 60 - 75 decibels under normal operating conditions.
(Slide of anti climber and collision post)
The 1200G is also built with an anti climber and 16 inch
deep I beam
collision posts on the short hood end for extra crew protection in the
case of collision with other railroad equipment or at railroad -
grade crossings. All collision protection meets AAR S-580
There are several safety features incorporated in the LNG fuel system
even though that LNG is difficult to ignite because of the very narrow
range of the air to fuel ratio that is required. Excess heat and
fuel pressure (greater than 80 psi) are removed by an economizer
that draws vapor from the top of the tanks while the engine is running
and passes the vapor to the engine. When the engine is shut down
the road relief regulator slowly vents vapor that is produced in the
(120-psi) through a vent at the top of the locomotive's long
This condition usually occurs when the locomotive has been sitting for
prolonged periods without use and consequently, the fuel begins to boil
off increasing vapor pressure. There are five 220 psi relief vent
valves on the locomotive; three on the vent tree inside the locomotive
car body and two on the fuel tank system. The vent tree also has
two 270 psi burst discs. The vaporizer has an 18-psi burst disc
the water side of the cooling system should a leak develop within the
The locomotive is equipped with six methane sensors for gas detection
that work through the microprocessor. Methane sensors are located
at each end of the fuel tanks: one below the radiators above the air
and one above the auxiliary generator on the expansion tank. In
one in the fresh air compartments below the inertial filter and one in
the cab. All of the sensors on the BNSF 1200Gs are set to
at a 10% Lower Explosive Limit (LEL) alarm level. Those on the UP
1200Gs are set at a 20% LEL. The sensors on all 1200Gs are set up
for non-intrusive calibration. The sensors provide uninterrupted
alarm capability with both audible and visual warnings. In the
of an alarm, strobe lights at each end of the locomotive (one on long
end and one on each side of the cab) are activated and an audible sound
warning is activated in the cab. There also is a normal
of standard, locomotive emergency, fuel cut-off buttons on the
CURRENT LOCOMOTIVE OPERATIONS - UNION PACIFIC
The Union Pacific locomotives, UP 1298 and UP 1299, are currently
to the UP's Commerce Yard just east of downtown Los Angeles,
Both units are assigned to general switching duties within the confines
of the yard. The UP performs all [sent] maintenance and servicing
functions, except fueling, to the locomotives with UP forces.
Since the maintenance is performed by the Union Pacific,
Company has a more limited access to the two locomotives. In
the two Union Pacific 1200Gs are equipped with a GPS system interfaced
with the 1200Gs micro processor system. Because of this, the UP does
download the microprocessor data on a regular basis. However, the
Union Pacific did download the duty cycle of UP 1299 for the period of
September 4, 1996, and January 31, 1997. Officials of the Union
and Boise Locomotive Company feel that this download represents a
duty cycle for the two Union Pacific 1200Gs. Through December 31,
1996, the UP 1298 engine operated 7,219 hours, averaging 8.68 hours for
each day in service. For the same period, the UP 1299 had 6,934
hours averaging of 8.33 hours for each in service day.
CURRENT LOCOMOTIVE OPERATIONS - BURLINGTON NORTHERN SANTA
The Burlington Northern Santa Fe locomotives, ATSF 1200 and ATSF 1201,
are currently assigned to BNSF Hobart just east of downtown Los
California. Both units have been assigned to general switching
within the confines of the yard until February of 1997. In
of 1997, the units were assigned to switching and local duty on the Los
Angeles Junction Railway (LAJ) in Vernon, California, a subsidiary of
BNSF. All maintenance and servicing, except fueling, is performed
by the Boise Locomotive Company at the LAJ facility a short distance
Limitations noted by the Burlington Northern Santa Fe are
1200 HP for
traction and the fuel tank size limits the locomotives to yard service,
because the units need to be operated near their fueling
The BNSF is pleased with the tractive effort of the 1200G. On
August 15, 1995, a tractive effort test was conducted by the ATSF on a
2.0% grade at mile post 27.0 on the Lucerne Valley Subdivision with
1201. The test location is at approximately 4100 feet elevation
the temperatures during the test time varied from 90oF to 96oF.
those conditions the 1201 produced slightly over 1000 HP. The
was conducted using test car ATSF 83 plus 19 loaded ballast cars with
Locomotive car number gross scale weight
Locomotive ATSF 1201 121.78 tons
Test Car ATSF 83 85.00 tons
Ballast Car ATSF 177037 94.05 tons
Ballast Car ATSF 176926 92.65 tons
Ballast Car ATSF 177183 91.10 tons
Ballast Car ATSF 177257 92.95 tons
Ballast Car ATSF 176945 95.75 tons
Ballast Car ATSF 177084 92.50 tons
Ballast Car ATSF 177376 94.40 tons
Ballast Car ATSF 177482 96.85 tons
Ballast Car ATSF 177586 94.35 tons
Ballast Car ATSF 177963 128.65 tons
Ballast Car ATSF 177047 94.80 tons
Ballast Car ATSF 177212 91.65 tons
Ballast Car ATSF 177893 114.45 tons
Ballast Car ATSF 177132 93.80 tons
Ballast Car ATSF 177681 92.95 tons
Ballast Car ATSF 177116 95.55 tons
Ballast Car ATSF 177469 94.60 tons
Ballast Car ATSF 177917 108.65 tons
The results of the test are as follows:
RUN TRAIN CONSIST BALANCE SPEED (MPH) TRACTIVE EFFORT
1 1201/ 10 cars 7.8 39,000 .18
2 1201/ 11 cars 6.6 44,400 .20
3 1201/ 13 cars 5.1 52,300 .23
4 1201/ 15 cars 3.6 61,000 .27
5 1201/ 17 cars 2.9 68,800 .30
6 1201/ 19 cars Stalled
7 1201/ 18 cars Stalled
Note: Adhesion coefficient "u" includes locomotive
Duty cycles of each unit downloaded from February 14, 1996, through
September 30, 1996 are virtually identical.
Officials of the Burlington Northern Santa Fe and the Boise Locomotive
Company feel this duty cycle represents a typical operation of the two
Through December 3,1996, the ATSF 1200 engine had operated
for an average of 14.53 hours for each day in service. For the
period, ATSF 1201 had 10,592 engine hours averaging 14.51 hours for
in service day.
LOCOMOTIVE FUELING - BURLINGTON NORTHERN SANTA FE
All fueling of the two BNSF 1200Gs is done at a modular TVAC
station that has been installed at LAJ locomotive service track in
This type of fueling station was chosen for its low cost of
based on low volumes of LNG the two BNSF units would be using.
The TVAC cryogenic pressure vessel capacity of 5,300 gallons of
The vessel is a double wall pressure vessel with vacuum insulation
of storing LNG at low pressures for several days. The vessel has
pressure relief valves and vents to release vapor pressure inside the
Tanks of this size will normally hold the LNG for 5 - 10 days before
depending on the tanks volume and the pressure upon delivery of the
The vessel is housed in a frame conforming to the specifications for an
ISO container. All fuel transfer equipment is skid mounted and
next to the pressure vessel. Instrumentation includes both
and electrical pressure gauges and level indicators. This system
will deliver between 40 and 50 gpm at pressures between 120 and 150
The system at the LAJ site has been permanently installed on concrete
pads with a concrete, spill retaining wall built completely around the
equipment to meet local codes.
Fueling of each locomotive is typically done once per
locomotives are spotted at the TVAC (each locomotive has a fuel fill on
each side) and the fuel fill nozzle from the TVAC is attached to the
tank receptacle. The LNG enters each tank through a top, fill
bar distributed through the vapor space to immediately reduce tank
to the saturation pressure of the incoming liquid. This
the need for venting the tank while fueling.
Low volume pumped by the TVAC
Safety checks are performed on the system prior to and after fueling.
The time it takes to condition the fuel before pumping can take up to
minutes to fuel the first locomotive and 20 to 30 minutes for the
All fuel is delivered by truck to the TVAC.
Total fuel used from start up of fueling operation in
December of 1994
through September 30, 1996, (last date of fuel reconciliation of fuel
to inventory) is 291,783 gallons: An average of 217.75 gallons per day
per locomotive for the period.
LOCOMOTIVE FUELING - UNION PACIFIC
Locomotive fueling for both Union Pacific 1200G switchers is
UP LNG fueling station located within Commerce Yard. While the
and fueling process is the same as with the TVAC at the LAJ, UTP was
as permanent facility capable of dispensing LNG to large volume road
and all equipment is therefore sized accordingly.
The fueling station at the UP consists of a permanent 55,000
50 psi, LNG bulk storage tank that can be filled by truck or rail
From the main, bulk storage tank, the fuel is pumped to a 3,000 gallon,
250 psi, LNG Transfer Tank where the fuel is conditioned prior to
the locomotives. From the LNG Transfer Tank the fuel is pumped to
the locomotives at 250 psi at a rate of approximately 100 gallons per
Fueling each 1200G at the UP typically takes approximately 25 minutes
the first locomotive and 15 minutes for the second locomotive.
The total fuel used from start of locomotive fueling on September 22,
1994, through September 30, 1996, (last date of reconciliation of fuel
deliveries to inventory) is 239,383 gallons. This is an average
161.96 gallons per day per locomotive.
LOCOMOTIVE FUELING PROCEDURE
While the fueling systems at both locations are different,
for fueling the locomotives does not differ at either location.
the LNG fueling procedure does differ from the normal, diesel fuel
The LNG fueling procedure is as follows:
"Blue flag" the locomotive.
Shut down the locomotive engine.
Ground the locomotive by attaching ground cable from locomotive fuel
tank to ground stake.
Cool down the fuel pump and fill equipment by circulating (normally
This procedure allows the liquid gas to reduce the temperature of the
pumping and filling equipment so that the liquid LNG does not become
when it flows through warmer equipment.
After cooling the special cryogenic fill connector on the fuel station
side it is connected to the special cryogenic fuel fill on the
Before pumping fuel into the locomotive, the road relief valve on the
locomotive must be closed to prevent vapor pressures from spiking and
Begin fueling and fill locomotive until the pressure gauge
After tanks are full, shut down fuel station pumping
Open locomotive load relief, valve on locomotive.
Remove fueling station, fill connection from locomotive.
Remove grounding cable from locomotive.
Remove blue flag.
LOCOMOTIVE SCHEDULED MAINTENANCE
The Boise Locomotive Company worked closely with Caterpillar
a scheduled maintenance program for the 1200G prior to the delivery of
the units to both railroads. The 1200G is a locomotive that, for
all purposes, is state-of-the-art in all respects when compared to
new DC motored locomotives being delivered with the only major
being the state-of-the-art LNG engine and fuel system. Therefore,
Boise Locomotive Company's recommended scheduled maintenance cycle for
the 1200G is the same as would be recommended for any new DC motored
with the exception of the LNG differences.
Boise Locomotive Company's initial scheduled maintenance for
3516 SITA engine and fuel system was conservative and with experience
time most of the maintenance functions scheduled on a 92 day basis have
been extended out. Functions that are over and above a typical
powered locomotive 92-day inspection are as follows:
Additional Inspection Requirements - 92 Day Inspection
Calibrate methane detectors 1.0
Calibrate ignition timing 1.0
Total additional man hours 92 day inspection 2.0
From experience, Boise Locomotive Company has determined
that the following
additional maintenance functions are required for the 1200G LNG
on an annual basis:
Function Man Hours/ Interval
Change oil as required by analysis not to exceed 1 year 2.0
Drain aftercooler condensation 0.5
Clean/set spark plug gap and adjust engine valve lash 8.0
Inspect fuel system valves/fittings and leak test 4.0
Replace gas regulator 1.0
Total additional man hours
All four 1200G locomotives have now been in service for over
Several items planned for replacement during the annual inspection and
two-year inspection were not necessary. Boise Locomotive Company
is continually monitoring the performance of the following items to
the optimum maintenance interval:
Replace spark plugs.
Replace oxygen sensors.
Replace engine thermostats.
Replace jacket water pump.
Replace aftercooler water pump.
Replace starter motors.
Replace water temperature thermostats.
All scheduled maintenance is still in the evaluation
It is Boise Locomotive Company's goal to extend all maintenance
as long as possible, however, different operating conditions may
revisions to the scheduled maintenance work scope and schedule.
Since the units were put in service, each Union Pacific
1200G has been
in operation for 863 days through January 31, 1997. Each BNSF
have been in service for 789 days through January 31, 1997.
the period of operation through January 31, 1997, there were 114
reported on all four 1200Gs. Failures reported are listed in
1. An analysis of the 114 reported defects breaks down as
Defect reported, none
The largest category of defects reported was 14.9% where
reported and none were found. Traditionally, there will always be
some defects reported with no defects found. However, the Boise
Company feels that the large number of reports of this type on the
is due to the prototype-type nature of the locomotives. Because
1200Gs have a new engine system, fuel system and control system
different from any that Boise Locomotive Company has ever produced
were probably several instances where the operator's noted a problem
the operator description, the maintainer's experience or lack of proper
diagnostics from the micro lead to no defect being found. A prime
example of this is the backfire problem reported several times, but no
defect was found until a later date.
The auxiliary generator defects at 13.2% of the reported defects took
several months to solve and the root cause of the defect was not
to the auxiliary generator itself. It was found that air born
was in the car body near the auxiliary generator. This debris was
being ingested by the auxiliary generator causing the brushes,
and slip rings to be coated with a film of dirt. To eliminate the
problem Boise Locomotive Company installed impingement filters over the
air vents on the auxiliary generator housing. Since the
of the impingement filters, there have been no auxiliary generator
The fuel pressure, fuel system and some of the no load defects were
for the most part due to problems with the LNG regulator (regulator
sticking). Two of the most serious LNG leak problems
when the plunger on the LNG regulator failed to close when the
would not start. This allowed LNG gas to flow through the intake
system, through the turbochargers into the fresh air room setting off
methane detectors. To eliminate this from occurring again Boise
Company revised the coding on the microprocessor to have the gas valve
to the regulator shut off if the engine does not start. In
it is Boise Locomotive Company's recommendation that the regulator be
out at every annual inspection since the plunger on the regulator will
eventually stick even when not in an engine start mode. Since the
regulators have been changed on a regular basis, the fuel system
have not occurred. A design change to the fuel regulator is being
investigated at this time.
The bulk of the control system, microprocessor and some of
the no load
problems were attributed to digital output board #2. This board
found to have an internal defect that has been corrected by the
of an external, noise suppression circuit. No other problems have
occurred since the installation of the noise suppression
A new board is in development now that will eliminate the need for the
noise suppression circuit.
The defects associated with methane sensors and other probes
to be directly related to moisture in the connections. An
sealing method at sensor and probe connections has all but eliminated
The defects associated with the LNG engine are deemed to be
of the infant
mortality variety except for the backfire, Engine Control Module (ECNP
and no start problems. Boise Locomotive Company believes that the
last three defects above are related to an inherent operational problem
related to engine design. The 3516 SITA LNG engine was originally
designed as an electrical power generation engine that typically runs
full load continually. From the duty cycles shown that appeared
it can be seen that the 1200G application of this engine is anything
a high, constant load application. In fact, the predominant
is in the idle position. Boise Locomotive, in conjunction with
has determined that when the LNG engine is running at idle or low
positions, the turbo boost pressure is low enough to allow the downward
stroke of the piston to create a vacuum in the cylinder. This
in turn was drawing oil past the valve umbrella seals, down the valve
into the cylinders resulting in oil deposits at the bottom of the
When the engine was operated in high load conditions these deposits
burn causing the ECM to sense an other than optimum engine operating
causing the engine to pre-detonate and shut down. The condition
allows deposits to form on the valve guides and valves and that may be
causing cold start problems. To date only one engine valve has
burnt on the ATSF 1200.
Caterpillar has developed a revised head for the LNG engine
tighter clearance on the valve guides, an improved seal with the single
lip seal replaced by a multiple lip seal (equivalent to 60 lip rings
inch). In addition, the valves are of two angle design rather than the
original single angle design. A full set of these new design
was installed on ATSF 1200 in January 1997, for testing. To
mitigate the problem Boise Locomotive Company recommends that the
be shut down when possible to reduce idling time.
To adequately measure how the above defects have been dealt with during
the service life of the 1200G, one can look at average days between
From the in service date for each 1200G through the end of 1995 (1,716
in service days) 84 defects (including no defects found) were reported.
This is an average days between reported failure of 20.42 days.
1996 (1,464 in service days), there were 30 defects (including no
found) reported for an average days between reported defects of 48.83
However, of the 1996 defects reported, 27 occurred in the
months. From July 1, 1996, through January 31, 1997, (860 in
days) there have only been three reported defects for an average days
reported defects of 286.67 days.
Availability of the units has not been tracked as the contracts that
Boise Locomotive Company has with the Union Pacific and the Burlington
Northern Santa Fe recognize that the 1200G are test locomotives.
Each contract contains clauses that allow the Boise Locomotive Company
a limited period to make repairs and adjustments before an availability
penalty applies. In all cases, Boise Locomotive Company has made
repairs to defects before the elapse time resulted in an availability
In most cases, repairs are made when the locomotives are in for fueling
or servicing or during their scheduled maintenance.
The 1200G test program on the Union Pacific and the
Santa Fe has been the only successful demonstration to date of the
and safety of using LNG as an alternative fuel. The 1200Gs have
that a LNG powered switcher locomotive can be operated and maintained
and safely much the same as conventional diesel powered switcher
I would like to thank the following individuals from the
Company who have contributed information and their time in the
of this paper:
David Brannan, Operations & Maintenance, BLC
Doug Graybeal, Service Department, BLC
Jim Larkin, Program Manager 1200G Program, BLC
John Reynolds, Service Department, BLC
I would also like to thank Mr. R. Bryan Morrison, formerly
of the ATSF,
for supplying the tractive effort test data performed by the ATSF.