Bachmann Spectrum SCV-42 (VIA Rail Charger) - HO

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Information on this wiki page provides particular details about this model not found in our basic guide.

Bachmann Spectrum SCV-42 Charger
SCV-42 Thumb.jpg
Model Information
Stock Number69001
Power TypeDCC Dual Mode w/Sound
Release DateFirst Run: Aug 2022
Retail Price499.95
Decoder Information
Decoder Type(?)WOWDiesel (OEM)
Sound Set(?)7
Lighting Functions10
Prototype Information
BuilderSiemens Mobility
Build DateMarch 2016 - Present
Motive PowerDiesel-Electric; Cummins QSK95
Cylinder CfgV16
Power Output4,200 hp (3,100 kW)
More Info[1]


Bachmann’s all-new DCC sound-equipped SCV-42 Charger uses Siemens Mobility’s original design documentation and authentic sound files recorded from the prototype. This model includes a TCS WOWSound® decoder with Audio Assist® for easy configuration without programming CVs, and on-board Keep-Alive® device for uninterrupted operation, even over dirty track. The WOWSound® diesel-electric locomotive sound package includes sounds for horn, bell, prime mover, air compressor, dynamic brakes, cooling fan, coupler close/release, brake release and application, and many more!

Loaded with prototypical features, the SCV-42 Charger in HO-scale from Bachmann Trains brings all the sights and sounds of Siemens' sleek new diesel-electric locomotive to your layout.

Features include:

  • Siemens-approved design
  • DCC sound-equipped for sound, speed, direction, and lighting control
  • Dual-mode NMRA-compliant decoder operates sound, motor, and lights on DCC or DC power.
  • TCS true CD-quality audio with 16-bit depth resolution at 44,100Hz
  • Authentic and prototypical sounds
  • Voice-guided Audio Assist® programming tool for easy set-up of almost all decoder functionality
  • On-board Keep-Alive® device that keeps your engine running during power interruptions due to dirty track or loss of electrical contact
  • Directional headlights with "Rule 17" dimming operation enabled by default
  • Interior corridor work lights
  • Forward-mounted High-beam light, with operation per prototype
  • Directional marker lights
  • Steady/alternate flashing ditch lights
  • TCS' industry-leading "quiet drive" Back EMF motor control for superior slow-speed performance and load compensation
  • User-loadable speed table options (3-point, 28-point, and 126-point curves)
  • Three select-able Throttle Modes
  • Two configurable Momentum Modes
  • TCS' new and exclusive Function Pagination System
  • Die-cast frame
  • Separately-applied windshield wipers, grab irons and other detail parts
  • Realistic top speed (limited in some cases by track voltage)

Specific Features

The SCV-42 charger is at its heart a WOWDiesel decoder but has had some customization to make it specific to the SCV-42 Charger locomotive. The information below details where CV’s and operation differ from the standard Diesel decoder.

DC mode operation

When operating in DC mode, the SCV-42 Charger locomotive will sit still until a sufficient track voltage is present. Once the minimum voltage is met the locomotive will begin to move. A horn blast and bell will activate automatically. Users may trigger a grade crossing horn quill sound by quickly adjusting the track voltage up and back down quickly. The directional horn blasts, quill, and automatic DC mode bell are enabled by default and are controlled by the Automatic Sounds CV.

Additional Sound Features

The SCV-42 Charger locomotive features new sounds such as “Whoosh” and “station announcements” as well as new traction noises like “traction motor” and “traction motor gearbox." Listen for the whine of the traction motors as the prime mover spools up and the Charger takes off. As the locomotive climbs toward 125 MPH, the traction motors are drowned out as the noise from the gearbox hardware hums ever louder.

The SCV-42 Charger supports an "automatic bell" in DCC mode. After the locomotive starts the bell will play until the DCC mode automatic bell cutout speed step is reached. Please refer to the CV Addendum (Indexed CV's) section below for more information.

The SCV-42 Charger includes a brand new Emergency Brake air dump sound. This sound will play if a user presses the Emergency Stop button on their throttle, if the Brake button is pressed 5 times in a row, or if the decoder goes into emergency via the "Crew Alert" feature.

The SCV-42 Charger is the first decoder from TCS to feature an industry-first feature straight from the prototype - the "3mph safety switch" - This feature will be active when the locomotive has the default horn set selected, or certain other prototype horns from Amtrak, such as the ACS-64 horn, or VIA Rail SC-42 horn. When any of the "high" versions of these horns are selected, the feature will activate. When the feature is active, the locomotive will automatically switch between the low-pressure and high-pressure outputs to the horn depending on the speed. The speed at which this change from low to high pressure happens is configurable in the decoder, but by default is roughly 3mph scale speed. This behaviour matches prototypical operations on most railroads, where only the low-pressure horn is available when stationary or at low speed, in order to reduce the volume of the horn while in passenger stations for example.

New Lighting Features

The SCV-42 Charger locomotive features a "high beam" headlight, positioned centrally on the front of the engine below the two primary headlights. According to the Siemens SCV-42 Charger Operations Manual, the high beam function can only be turned on when the headlight is active and not dimmed. TCS has implemented automatic and manual control modes for the high beam. The factory default is set to automatic control (CV182 bit 7 is ON). In automatic mode the high beam will behave as described in the Siemens manual. When Function 5 in Light Mode is activated, the high beam will turn on only when the headlight is active and not dim. If Function 5 in Light Mode is turned off, the high beam will remain off regardless of current headlight state. In manual control mode (CV182 bit 7 is OFF), headlight status has no effect on the high beam. The high beam is controlled manually by the throttle button 5 in Light Mode.

Button Mappings

The values outlined below in the button mapping, sound list, and CV values are the defaults assigned to this particular decoder from the factory.

For information on how to program your locomotive using the values provided in the charts below, please see our Comprehensive Programming Guide, WOWDiesel V4 Programming Guide, and/or List of Standard CV's.

TCS Function Pagination System

The Bachmann Spectrum SCV-42 (VIA Rail Charger) - HO locomotive supports TCS' new "function pagination" system. This makes it easy to access all 28 functions and all lighting effects on throttles with limited function access by adding an offset to the pressed function button (offset of +10 for function page 2; offset of +20 for function page 3). For example, to access function 15:

  • Press function 8 twice to rotate through the function pages until the decoder announces "function page [two]"
  • Press button 5 on your throttle/controller
  • The decoder will activate function 5 + 10 (page 2 offset) = 15

Note: the decoder supports accessing functions above 9 at any time by pressing the corresponding button(s) on your throttle regardless of the currently selected function page.

If you have a command station which supports all 28 function buttons and would like to disable function pagination, this may be done by re-configuring the User Options indexed CV 4:19. For more information on the User Options indexed CV for Version 4 WOWSound Diesel decoders, please see Page 19 of the WOWSound Diesel Version 4 Complete Programming Guide. This document can be used in conjunction with the Indexed CV Addendum below.

To disable Function Pagination, set the values of the Indexed CV as follows:

  • CV 201 = 4
  • CV 202 =19
  • CV 203 = 144
  • CV 204 = 251
Button Mappings
Function Button Sound Action Light Action Dual Enabled Page and Button
0 None Headlights Yes Page 1 Button 0
1 Bell Blink Ditch Lights Yes Page 1 Button 1
2 Horn - Long Blast Blink Ditch Lights Yes Page 1 Button 2
3 Horn - Short Blast Ditch Lights (on/off) No Page 1 Button 3
4 Whoosh Number Board Lights No Page 1 Button 4
5 Train Brake High Beam (on/off) No Page 1 Button 5
6 Startup/Shutdown Marker Lights (on/off) No Page 1 Button 6
7 None Dim Headlights Yes Page 1 Button 7
8 1x Press Mute/Unmute
2x Press rotate light/sound mode or page
4x Press Audio Assist™
None Yes Page 1 Button 8
9 Dynamic Brake Corridor Lights No Page 1 Button 9
10 Manual Notch Up Ditch Lights Blink No Page 2 Button 0
11 Manual Notch Down Emergency Strobe (on/off) (or with 5x brake press or with E-STOP function) No Page 2 Button 1
12 Coupler Close None No Page 2 Button 2
13 Coupler Release None No Page 2 Button 3
14 Brake Release None No Page 2 Button 4
15 Traction Motor Blower None No Page 2 Button 5
16 Momentum None No Page 2 Button 6
17 Crew Alert None No Page 2 Button 7
18 1x Press Mute/Unmute
2x Press rotate light/sound mode or page
4x Press Audio Assist™
None No Page 2 Button 8
19 Random Whoosh (on/off) None No Page 2 Button 9
20 Grade Crossing Quill None No Page 3 Button 0
21 Forward Quill None No Page 3 Button 1
22 Reverse Quill None No Page 3 Button 2
23 Stop Horn None No Page 3 Button 3
24 Rotate Bell/Horn None No Page 3 Button 4
25 Windshield Wipers None No Page 3 Button 5
26 Station Announcements Departing None No Page 3 Button 6
27 Station Announcements Arriving None No Page 3 Button 7
28 1x Press Mute/Unmute
2x Press rotate light/sound mode or page
4x Press Audio Assist™
None No Page 3 Button 8
Random Sound Mapping
1 Air Compressor
2 None
3 Dust Blower
4 Whoosh (When enabled with F19)

CV Addendum (Standard CV's)

The SCV-42 Charger follows the motor and lighting CV's as described in TCS's Comprehensive Programming Guide. Listed below are the CV's that have been modified for the Charger decoder.

CV Number CV Value Description
CV3 6 Acceleration
CV4 6 Deceleration
CV13 247 DC Mode lights
CV29 6 Configuration CV
CV35 16 Light output 1 mapped to F3
CV36 16 Light output 2 mapped to F3
CV39 16 Light output 3 (brown wire) mapped off of F3
CV40 64 Light output 4 (pink wire) mapped to F5
CV49 8 Front headlight uses Rule 17
CV50 24 Rear headlight uses Rule 17
CV51 10 Light output 1 is a Ditch light
CV52 11 Light output 2 is a Ditch light
CV54 0 Light output 4 (pink wire) is constant bright light (forward only) - High Beam
CV61 41 Configuration CV
CV63 10 Ditch light blink holdover time
CV117 221 Ditch light blink rate
CV123 0 Removes Rule17 Dimming Mapping from Buttons 0-6
CV124 76 Ditch lights blink (F0-F6) on buttons 1, and 2
CV158 4 Enables Rule17 dimming on F7
CV159 32 Ditch lights blink (F7-12) on button 10
CV182 134 Disabled motor delay (motor changes speed right after throttle is changed, no delay), activate automatic control of the high beam.
CV189 0 Dynamic brake min speed set to 0
CV190 10 Rate of deceleration from Dynamic Brakes
CV191 10 Dynamic Brake speed decrease (in speed steps) per press of the dynamic brake button
CV248 7 Sound Set Revision Identifier. First Run = 7

CV Addendum (Indexed CV's)

The SCV-42 Charger follows the motor and lighting CV's as described in TCS's WOWDiesel Programming Guide. Listed below are the TCS Indexed CV's that have been modified for the SCV-42 Charger decoder.

[The Sound type "Air Spitter" was re-named to "Dust Blower" in Audio Assist]

[The Sound type "Sanding Valve" was re-named to "Emergency Brake" in Audio Assist]

Indexed CV Number Indexed CV Value (CV203,CV204) Description
8 0,3 Default to new VIA Charger Horn
9 0,0 Charger defaults to Traditional throttle mode
10 0,80 Default Master Volume of decoder
11 0,0 Only one prime mover is available in the Charger decoder
12 255,2 Enable all DC mode automatic sounds
14 1,15 F0, 1, 2, and 7 dual mode enabled (active in light and sound mode)
15 0,0 Dynamic brake notch setting - Notch down to idle under dynamic braking as per prototype
17 0,17 BEMF LOW Calibration
18 0,40 BEMF HIGH Calibration
19 SR: 208,251 "USER OPTIONS" Indexed CV - bitwise (inclusive selection):

(0)*  Enable Manual Notching audio feedback sound (1)*  Automatically notch down prime mover when brakes are on (2)   Mute on startup/engine auto start mute if set (3)*  Enable switch/mainline mode audio feedback (4)*  Enable Rotate horn/bell audio feedback (5)*  Enable lightmode/sound mode audio feedback (6)*  Enable Audio auto shutoff timer (7)*  Digitrax bit-set simulates button 2 as toggle while in A.A. mode (8)   Dual Prime Movers - Set to enable (9)   Prime mover notches up with dynamic brakes (10)  Reverse directional horns (11)  Switching mode prime mover mechanism, if set prime mover will jump notch, otherwise it will stair step (default) (12)* Mainline mode prime mover mechanism, if set prime mover will jump notch (default), otherwise it will stair step (13)  Bypass corridor light timer (14)* Enable Bachmann Function Pagination (Not available in First Run models) (15)* Grade Crossing Quill sound blinks ditch lights (Not available in First Run models) Items marked with an asterisk (*) are set by default. First-Run VIA Rail default values: CV203 = 208; CV204 = 251 [11010000 11111011]

23 0,0 Bell Selection - Only 1 bell available (E-bell)
32 0,10 Notch 2 speed step (traditional throttle mode)
33 0,25 Notch 3 speed step (traditional throttle mode)
34 0,35 Notch 4 speed step (traditional throttle mode)
35 0,50 Notch 5 speed step (traditional throttle mode)
36 0,60 Notch 6 speed step (traditional throttle mode)
37 0,70 Notch 7 speed step (traditional throttle mode)
38 0,80 Notch 8 speed step (traditional throttle mode)
43 5,0 DC Mode start voltage – Voltage at which the engine will start making noise in DC mode, the higher the value the higher the voltage
44 5,70 Voltage at which the DC mode bell will stop playing, the higher the value the higher the voltage threshold.
45 0,15 Speed step in DCC mode that the automatic bell will stop playing at
46 1,144 DC Mode motor hysteresis – When the engine starts moving in DC mode the increased current draw may cause some oscillation, if so increase the value in this CV until the oscillation goes away. If the engine is going through a power on reset try increasing Sound CV 43 (Voltage at which the Engine will power up at while in DC mode)
50 0,6 “Switching momentum” mode acceleration value
51 0,6 “Switching momentum” mode deceleration value
58 0,7 High Horn Threshold (5mph safety switch)

*NEW FEATURE* Speed step at which the decoder will begin playing the High-Pressure Horn. When the speed is set to below this value, the decoder will use the low-pressure horn. A value of 0 disables this feature, and the high horn will always play. A value of 1 will only play the low horn when stationary.

(Valid Values = 0-126)

NOTE: This feature only applies to specific horns, and does not apply to all horn sets available on this decoder.


Decoder Service and Repair

For service/repair, contact the Bachmann Service Department by visiting, calling 1-800-356-3910 (toll-free within the U.S. and Canada), or emailing Bachmann’s Service Department is available Monday thru Friday, 8:30 AM to 4:30 PM ET.

You can also send your locomotive to: Bachmann Trains Service Department 1400 East Erie Avenue Philadelphia, PA 19124

Please include a detailed description of your concern and complete contact information. For some service issues regarding DCC sound decoders, the Bachmann Service Department may forward your locomotive to TCS for resolution.