U25C

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

U25C
Model Information Manufacturer Korea Brass Scale HO-Scale Power Type DCC Dual Mode w/Sound Release Date 2025 Retail Price $249.95 Decoder Information Decoder Type(?) WOW101-Diesel Version(?) 4.5 Lighting Functions 4 Prototype Information Builder GE Transportation Systems Build Date September 1963 - December 1965 Motive Power Diesel Cylinder Cfg 16 Power Output 2,500 hp (1,860 kW) More Info [1]

Overview

TCS Locomotive Works DCC sound-equipped U25C includes a TCS WOWSound® decoder with factory-preset prototypical sound configuration. This model also includes Keep-Alive® for uninterrupted operation, even over dirty track. The WOWSound® Diesel locomotive sound package includes sounds for horn, bell, prime mover, air compressor, cooling fan, coupler close/release, brakes, and many more! (See below)

Specific Features

Features include:

• 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 (16-bit, 44,100Hz)
• Authentic and prototypical sounds set by default
• Over 50 whistle and over 40 bell options
• Keep-Alive® included, which 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
• 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)
• Two select-able Throttle Modes
• Two configurable Momentum Modes
• Die-cast frame

Additional Features

The U25C is at its heart a WOWDiesel decoder but has had some customization to make it specific to the locomotive. The information below details where CV’s and operation differ from the standard Steam decoder.

DC mode operation

When operating in DC mode, the locomotive will sit still and silent until a sufficient track voltage is present. Once the minimum voltage (approximately 8 volts) is met, the locomotive will ignite the prime mover and the lights will come on. An additional increase in voltage will cause the locomotive to begin to move. A directional horn blast will sound, and the bell will activate automatically. Increasing the voltage further will shut off the automatic bell. 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.

Note: This WOWSound® product includes TCS' Audio Assist® auditory feedback program.

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 Programming Guide, and/or List of Standard CV's.

Button Mappings
Function Button	Sound Action	Light Action	Dual Enabled	Page and Button
0	None	Headlights	Yes	Page 1 Button 0
1	Bell	None	No	Page 1 Button 1
2	Whistle - Long Blast	None	No	Page 1 Button 2
3	Whistle - Short Blast	None	No	Page 1 Button 3
4	Blow Down	None	No	Page 1 Button 4
5	Cylinder Cox	None	No	Page 1 Button 5
6	Water Fill	None	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	None	None	No	Page 1 Button 9
10	Blower	None	No	Page 2 Button 0
11	Injector	None	No	Page 2 Button 1
12	Coupler Crash	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	Train Brakes	None	No	Page 2 Button 5
16	Momentum	None	No	Page 2 Button 6
17	Safety Valve	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	None	None	No	Page 2 Button 9
20	Grade X 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 Quill	None	No	Page 3 Button 3
24	Rotate Bell/Horn	None	No	Page 3 Button 4
25	Ash Pan Cleaning	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
Random Sound Generator	Sound Played
1	Air Compressor
2	None
3	Injectors
4	Safety Valve

Sound List

Please refer to the WOWDiesel Version 4.5 Sound List for a complete list of sounds included on this decoder.

CV Addendum (Standard CV's)

The U25C follows the motor and lighting CV's as described in in TCS' Comprehensive Programming Guide and List of Standard CV's. Listed below are the CV's that have been modified for the U25C decoder.

CV	Value	Description
CV 3	6	Acceleration Rate
CV 4	6	Deceleration Rate
CV 49	40	F0F light feature
CV 50	24	F0R light feature
CV 51	33	F1 light feature
CV 61	41	Configuration CV #2
CV 139	0	Brake Button Remapping (0-6)
CV 123	0	Rule 17 Dimming Button Remapping (0-6)
CV 158	4	Rule 17 Dimming Button Remapping (7-12)
CV 177	0	BEMF Overall Responsiveness
CV 179	4	BEMF Low-Speed Sensitivity
CV 181	6	BEMF Critical Speed Step

CV Addendum (Indexed CV's)

The U25C decoder follows the motor and lighting CV's as described in TCS's WOWDiesel Programming Guide. Listed below are the TCS Indexed CV's for the U25C decoder:

Sound CV's

The table below lists all of the Indexed CV's used to configure "sound-related features" of the decoder. To use the information in this table, first program CV 204 with a value of 4, CV 202 with the value shown in the first column, and then use CV 203 and CV 204 to change the configuration.

Sound CV's (CV 201 = 4)

Indexed CV (CV202)	Indexed CV Value (CV203,CV204)	Description
8	0,7	Whistle Type Selection (New York Central Hudson 5-chime)
10	0,40	Master Volume
11	0,4	Locomotive Type
14	3,3	Dual-Enabled Functions
19	128,248	User Options (0) Enable CAM (1) Enable Layout Sound (Disabled in Gen. 1) (2) Enable Mute on startup (3)* Allow Articulated Chuff to Slip (4)* Enable Rotate whistle/bell Audio feedback (5)* Enable Light Mode/Sound Mode Audio feedback (6)* Enable Audio auto shutoff timer (7)* Use momentary button 2 as toggle while in Audio Assist (8) Enable Articulated Chuff (9) [not used] (10) Reverse Directional Whistles (11)* Enable Power Braking (12)* Enable Momentum Mode Audio Feedback (13)* Enable Johnson Bar Audio Feedback (14) Enable Function Pagination||NOTE: Set to Enabled by default for Bachmann OEM decoders (15) [reserved]
23	0,7	Minimum Chuff Volume
24	0,19	Bell Type Selection (New York Central Hudson Bell)