637K Wheel Tractor – Coal Bowl Scraper



Technical Specifications
Benefits and Features

637K coal bowls are longer and higher than standard wheel tractor scraper bowls, allowing them to haul 38 m (50 yd) of low density loose coal. The bowls are designed and built to specifically deliver in coming loose coal to the stock pile and reserve stock piled coal to the feeder system.

Flywheel Power - Tractor/Scraper 425 kW (570 hp)/216 kW (290 hp)
Operating Specifications
Scraper Capacity - Heaped 50 yd³
Top Speed - Loaded 34.7 mile/h
Exterior Sound Power Level The exterior sound power level for the standard machine (ISO 6393:2008) is 118 dB(A).
ROPS/FOPS Meet ISO standards
Axle to Vertical Hitch Pin 20 in
Front of Tractor to Front Axle 142.2 in
Ground Clearance - Tractor 26.1 in
Height - Overall Shipping 163 in
Height - Scraper Blade Maximum 21.2 in
Height - Top of Cab 147 in
Length - Overall Machine - Standard 609.5 in
Rear Axle - Rear of Machine 95.4 in
Width - Inside of Bowl 134 in
Width - Outside Rear Tires 143.2 in
Width - Overall Machine 155 in
Width - Rear Tire Centers 96.9 in
Width - Tractor 137.8 in
Wheel Base 377 in
180° Curb-to-Curb Turning Width 42.59 ft
Emissions Cat C9.3 and Cat C18 engines meet U.S. EPA Tier 4 Final/EU Stage IV engine emission standards.
Engine Model - Scraper Cat C9.3
Engine Model - Tractor Cat C18
Flywheel Power - Scraper 290 HP
Flywheel Power - Tractor 570 HP
Fuel Tank Refill Capacity - Scraper 370 gal (US)
Maximum Depth of Cut 17.7 in
Maximum Depth of Spread 21.1 in
Operating Weight - Empty 117782 lb
Overall Length 609.5 in
Overall Shipping Height 13.62 ft
Overall Width 12.93 ft
Rated Engine RPM - Scraper 2150 r/min
Rated Engine RPM - Tractor 1900 r/min
Rated Load 34 472 kg (76,000 lb)/34.20 tonnes (38 tons)
Scraper Capacity - Heaped 50 yd³
Scraper Capacity - Struck 41 yd³
Tires - Scraper 37.25R35**E3
Tires - Tractor 37.25R35**E3
Top Speed - Loaded 34.7 mile/h
Width - Cut 11.5 ft
Implement Cycle Times
Apron Lower 3.8 s
Apron Raise 4 s
Bail Lower 2.1 s
Bail Raise 1.5 s
Bowl Lower 3.5 s
Bowl Raise 3.5 s
Ejector Extend 8.5 s
Ejector Retract 8.5 s
Safety Criteria Compliance Standards
Brakes ISO 3450:2011
Falling Object Protective Structure (FOPS) ISO 3449:2005 Level II
Reverse Alarm ISO 9533:2010
Rollover Protection Structure (ROPS) ISO 3471:2008 for up to 21 282 kg (46,919 lb)
Seat Belt SAE J386:FEB2006
Steering System ISO 5010:2007
Service Refill Capacities
Cooling System - Scraper 16.1 gal (US)
Cooling System - Tractor 19.8 gal (US)
Crankcase - Scraper 6.5 gal (US)
Crankcase - Tractor 13.7 gal (US)
Diesel Exhaust Fluid - Scraper 5.8 gal (US)
Diesel Exhaust Fluid - Tractor 8 gal (US)
Fuel Tank 370 gal (US)
Hydraulic System 37.5 gal (US)
Transmission System - Scraper 12.9 gal (US)
Transmission System - Tractor 29 gal (US)
Travel Speeds - Runout
Transmission Gear - Eighth 34.7 mile/h
Transmission Gear - Fifth 14.1 mile/h
Transmission Gear - First 3.4 mile/h
Transmission Gear - Fourth 10.5 mile/h
Transmission Gear - Reverse 6.2 mile/h
Transmission Gear - Second 6.2 mile/h
Transmission Gear - Seventh 25.7 mile/h
Transmission Gear - Sixth 19 mile/h
Transmission Gear - Third 7.7 mile/h


  • Coal Bowls are longer and higher than standard scraper bowls, which allows Wheel Tractor-Scrapers to haul 38 m (50 yd) of low density loose coal. The bowls are designed and built to specifically deliver in coming loose coal to the stock pile and reserve stock piled coal to the feeder system.
  • Sequence Assist (optional) uses cylinder position sensors to automate bowl, apron and further implement controls throughout the four core work cycles: Dig, Haul, Unload and Return. When utilized this can reduce up to 14 individual operator commands per cycle. Sequence Assist simplifies control over the implements, reduces joystick usage, automatically controls cushion hitch, transmission hold and ejector.


  • The fuel, water and engine oil are relocated at ground level on the right hand side of the machine for easy access.
  • In cold weather conditions the machine will use the Auto Stall feature to help warm up the transmission oil faster resulting in the machine shifting out of torque converter drive (2nd gear) faster than on previous models.


  • Brakes have been changed from an air actuated drum shoe brake to a hydraulic actuated tractor wet disc brake and a scraper dry caliper.
  • Tire Spin Reduction allows the machine to control the slip of the tractor tires only. When Tire Spin Reduction is selected the machine will control wheel spin on the tractor by keeping the slip in the optimal range for loading by adjusting engine rpms with no additional operator input.
  • Engine Over Speed Protection - In the event of an engine over speed situation, the compression brake or brakes will automatically engage with no operator input. The machine determines the over speed condition based on rate of acceleration and applies compression brakes automatically.
  • Differential Lock Engagement Protection allows the machine to prevent the operator from engaging the differential lock when damage could occur.
  • Coal bowl scrapers are effective in compacting coal, which reduces the risk of spontaneous combustion of coal in the stockpile by eliminating the air spaces.


  • Advanced Cushion Hitch allows the cushion hitch to prevent end stroke by having the ability to predict end stroke events and manage the rate of dampening. Resulting in reduced hitch maintenance and improved operator ride in rough conditions.
  • The K Series steering system design requires significantly less steering effort. The reduced steering effort will allow for decreased operator fatigue and a more efficient operator resulting in possible higher rates of production late in the work cycle.
  • The K Series cab interior improves operator comfort and visibility. The overall interior is 21% larger than the G Series cab.


  • Machine Speed Limitis designed to take the place of top gear selection. If the machine top speed needs to be limited the operator can select the top speed through the display or the top speed can be set in ET. This will allow the machine to find the correct gear that works best for the engine and transmission. Allowing the engine and transmission to select the correct gear to pull the load in most cases resulting in a lower engine load factor and lower fuel burn verses using top gear selection that required the machine to run at engine speeds at or close to high idle.
  • Ground Speed Control sets the desired top speed by the operator if job site conditions or segment speed limits require a speed less than full run out. Machine Speed Limit is intended for use when top speed needs to be limited for longer durations and Ground Speed Control is intended for use when the top speed needs to be reduced for shorter segments or intermediate periods of time. The operator can set the desired top speed and the machine will find the correct gear that works best for the engine and transmission. In most cases, allowing the engine and transmission to select the correct gear to pull the load will result in a lower engine load factor and lower fuel burn verses top gear selection.
  • Fuel Economy Mode is a two part feature when selected, the first part of the feature lowers the transmission shift points allowing shifting to take place at lower rpms to aid in fuel savings. The second part of the Fuel Economy Mode allows the machine, when operated at engine rpms less than full throttle, to automatically vary the power distribution between the tractor and the scraper, allowing the machine to utilize the more efficient tractor power train vs. the full time torque convertor drive scraper power train.

Standard Equipment:

  • Power Train – Tractor
    • Cat C18 engine with MEUI
    • Compression engine brake
    • Electric start, 24V
    • Air cleaner, dry type with precleaner
    • Fan, hydraulic
    • Ground level engine shutdown
    • Radiator, aluminum unit core, 9 fins per inch
    • Guard, crankcase
    • Starting aid, ether
    • Braking system:
      • Primary and secondary, wet disc, hydraulic actuated
      • Parking, hydraulic-released, spring-applied
    • Throttle lock
    • Transmission:
      • 8-speed planetary power shift
      • ECPC control
      • APECS software
      • Programmable top gear selection
      • Transmission hold
      • Differential lock
      • Guard, power train
      • Standard tire spin reduction
      • Ground speed control
      • Machine speed limit
      • Differential lock protection
  • Power Train – Scraper
    • Cat C9.3 engine
      • High pressure common rail fuel
      • Constant lift engine brake
    • Electric start, 24V
    • Air cleaner, dry type with precleaner
    • Fan, mechanical driven
    • Ground level engine shutdown
    • Radiator, aluminum unit core, 9 fins per inch
    • Starting aid, either
    • Braking system:
      • Primary and secondary, dry caliper, hydraulic actuated
    • Transmission:
      • 4-speed (torque converter drive)
      • Planetary power shift
  • Electrical – Tractor
    • Alternator, 150 Amp
    • Batteries (4), 12V, 1,000 CCA, maintenance free, high output
    • Electrical system, 24V
    • Lighting system:
      • Headlights, LED
      • Turn signals with hazard function, LED floodlights, (2) cutting edge (1) bowl, halogen side vision (2)
    • Starting/charging receptacle
  • Electrical – Scraper
    • Alarm, backup
    • Batteries (4) 12V, 1,000 CAA, maintenance free, high output
    • Alternator, 65 Amp
    • Electrical system, 24V
    • Lighting system:
      • Brake lights, LED
      • Turn signals with hazard function, LED
  • Operator Environment – Tractor
    • HVAC system, heat, AC, defrost
    • Thermostat control of HVAC system
    • Coat hook
    • Lunchbox platform with holding strap
    • Diagnostic connection (2)
    • 12V power ports (2)
    • Differential lock (1)
    • Dome courtesy light
    • Horn, electric
    • T-handle implement control
    • Mirror, rearview
    • Radio ready
    • ROPS/FOPS cab, pressurized
    • Keypad switches:
      • Throttle lock
      • Wipers/washers
      • Hazard lights
      • Retarding level select
      • Work lights on, off
      • Information mode on Messenger Display
    • Safety tab rocker switches
    • Seat belt, static two-piece
    • Seat, Cat Advanced Ride Management (ARM), Cat Comfort Series 3, rotates 30 degrees
    • Steering wheel, tilt, telescoping, padded
    • Windows, right side emergency egress
    • Windows, sliding
    • Windows, laminated, zipped in
    • Windshield wipers, front and rear windows, includes washers
    • Door lock
    • Messenger Display
    • Gauges, warnings include:
      • Coolant temperature
      • Engine oil temperature
      • Hydraulic oil temperature
      • Fuel level
      • Park brake
      • Implement lockout
      • Brake system
      • Throttle lock
      • System voltage
      • Secondary steering
      • Bail down
      • Ejector auto
      • Differential lock
      • Apron float
      • Transmission hold
      • Cushion hitch
      • High beam lights
      • Action lamp
      • Engine speed, rpm
      • Gear selection
  • Fluids
    • Extended Life Coolant to –37° C (–34° F)
  • Other Standard Equipment – Tractor
    • Advanced cushion hitch
    • Accumulators (cushion hitch) with Canadian Registration Number (CRN)
    • Fast oil change
    • Fenders, non-metallic
    • Heater, engine coolant 120V
    • Rims (2)
    • Tow hooks, front
    • Vandalism locks
    • Heater, engine coolant 120V
    • Steering locks
  • Other Standard Equipment – Scraper
    • Coal Bowl
      • 31 m3 (41 yd3), struck
      • 38 m3 (50 yd3), heaped
    • Vandalism locks
    • Scraper fenders
    • Fast oil change
    • Rims (2)
    • Hydraulic position sensing cylinders (bowl lift and apron)

Optional Equipment:

  • Steering Arrangements
    • Secondary Steering Arrangement
  • Integrated Technologies
    • Sequence Assist Arrangement
    • Advanced Tire Spin Reduction
  • Other Attachments
    • Camera arrangement – WAVS
    • Cab beacon
    • Air horn
    • Air horn and beacon
    • Wiring group
  • Service Instructions
    • Film arrangement – U.S. (ANSI)
    • Film arrangement – International (ISO)
For our customers, we remain open to serve you; however, we are temporarily limiting access at all locations to employees only. 
For parts customers, we will be providing a curbside pickup option at many of our facilities. We encourage you to call your local NMC location or use our online services to order parts or schedule service.
 While these are challenging times, we’ll continue to make the decisions that best support you and our team. Please visit this page for more information.