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 6 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 List of Standard CV's for WOWSound Version 5, and/or List of Indexed CV's for WOWSound Version 5.

Button Mappings
Function Button	Sound Action	Light Action	Dual Enabled	Button
0	None	Rule 17 - Both Directions - Lamp 0F	False	Button 0
1	Bell	Constant Bright - Both Directions - Lamp 1	False	Button 1
2	Horn Long	Constant Bright - Both Directions - Lamp 2	False	Button 2
3	Horn Short	None	False	Button 3
4	Horn Quill	None	False	Button 4
5	Brake Squeal	None	False	Button 5
6	Prime Mover Ignition	None	False	Button 6
7	None	Special Function: Dim the Rule 17 Light	True	Button 7
8	1x Press Mute/Unmute 2x Press to rotate page 4x Press Audio Assist™	None	True	Button 8
9	None		False	Button 9
10	Manual Notch Up	None	False	Button 10
11	Manual Notch Down	None	False	Button 11
12	Coupler Clank	None	False	Button 12
13	Coupler Clank	None	False	Button 13
14	Brake Release	None	False	Button 14
15	Dynamic Brake	None	True	Button 15
16	Momentum	None	True	Button 16
17	Crew Alert	None	False	Button 17
18	1x Press Mute/Unmute 2x Press to rotate page	None	True	Button 18
19	None	None	False	Button 19
20	Air Spitter	None	False	Button 20
21	Forward Sound	None	False	Button 21
22	Reverse Sound	None	False	Button 22
23	Stop Sound	None	False	Button 23
24	Rotate Whistle	None	False	Button 24
25	Windshield Wipers	None	False	Button 25
26	Exhaust Fan	None	False	Button 26
27	None	None	False	Button 27
28	1x Press Mute/Unmute 2x Press to rotate page	None	True	Button 28

Random Sound Mapping
Random Sound Generator	Sound Played
1	Air Compressor
2	Air Spitter
3	None
4	None

Sound list

Sound Type	Sound Number	High Byte	Low Byte	Sounds Available
Air Compressor	0	0	0	EMD Air Compressor Type 1
Air Spitter	1	0	1	Air Spit #1
	2	0	2	Air Spit #2
Brake Release	8	0	8	Brake Release
Brake Squeal	9	0	9	Brake Squeal *
Coupler Clank	39	0	39	Coupler Clank Closed
	40	0	40	Coupler Clank Open
Dynamic Brake	42	0	42	Dynamic Brakes
	43	0	43	Dynamic Brakes Medium
	44	0	44	Dynamic Brakes High
Exhaust Fan	45	0	45	Exhaust Fan
Forward Sound	46	0	46	Forward Sound *
Horn Quill	62	0	62	Horn Quill *
Horn Short	70	0	70	Horn Short *
Manual Notching	78	0	78	Manual Notch Down
	79	0	79	Manual Notch Up
Momentum Mode	80	0	80	Momentum Feature
Mute	82	0	82	Mute Audio
Prime Mover Ignition	159	0	159	Prime Mover Ignition *
Reverse Sound	161	0	161	Reverse Sound *
Stop Sound	177	0	177	Stop Sound *
Windshield Wipers	185	0	185	Windshield Wiper

*For Prime Mover, Bell, and Horn custom reprogramming use the sound numbers below in the corresponding CV from the table header

Prime Mover

CV 123 Value	Active Prime Mover
0 (default)	EMD 567D2 16 Turbo

Bell

CV 122 Value	Active Bell
0 (default)	GP20 WP #2100 Bell
1	Conrail Num 2233 GP30 Air Powered Bell
2	VO 1000 Bell
3	Western Pacific 713 Bell
4	Western Pacific 918D F Unit Bell

Horn

CV 120 Value	Active Horn
0 (default)	Leslie 3 Chime
1	Leslie RS3
2	Leslie RS3L
3	Nathan K3
4	Nathan K3H
5	Nathan M3 C.P. 1
6	Nathan P3
7	Wabco E2 3 Chime Horn

CV Addendum (Standard CV's)

The U25C follows the motor and lighting CV's as described in in TCS' Complete Standard CV's List For WOWSound Version 5. Listed below are the CV's that have been modified for the U25C decoder.

CV	Value	Description
CV 3	5	Acceleration Rate
CV 4	5	Deceleration Rate
CV 49	40	F0F light feature
CV 50	40	F0R light feature
CV 61	33	Configuration CV #2
CV 115	0	Motor Delay Reset Time
CV 120	0	Horn Set Selector
CV 123	0	Prime Mover Selection
CV 126	7	Rule 17 Dimming Button Remapping
CV 142	225	Random Sound 2 Frequency
CV 177	48	User Options #2
CV 197	25	Volume - Bell
CV 204	20	Volume - Exhaust Fan
CV 213	55	Volume - Prime Mover
CV 214	55	Volume - Prime Mover Ignition
CV 219	30	Volume - Windshield Wipers
CV 238	129	Dual Enabled functions register 1 (F0-F7)
CV 241	0	Dual Enabled functions register 4 (F24-F28)
CV 247	71	None Supplied
CV 249	182	Decoder Hardware Model Identifier

CV Addendum (Indexed CV's)

The U25C follows the motor and lighting CV's as described in TCS' List of Indexed CV's for WOWSound Version 5. Listed below are the CV's that have been modified for the U25C decoder.

CV31	CV32	CV	Value	Description
16	4	260	3	Sound Mapping - F1
16	4	262	54	Sound Mapping - F2
16	4	264	70	Sound Mapping - F3
16	4	266	62	Sound Mapping - F4
16	4	268	9	Sound Mapping - F5
16	4	270	159	Sound Mapping - F6
16	4	272	65535	Sound Mapping - F7
16	4	274	82	Sound Mapping - F8
16	4	276	65535	Sound Mapping - F9
16	4	278	79	Sound Mapping - F10
16	4	280	78	Sound Mapping - F11
16	4	282	39	Sound Mapping - F12
16	4	284	40	Sound Mapping - F13
16	4	286	8	Sound Mapping - F14
16	4	288	42	Sound Mapping - F15
16	4	290	80	Sound Mapping - F16
16	4	292	41	Sound Mapping - F17
16	4	294	83	Sound Mapping - F18
16	4	298	1	Sound Mapping - F20
16	4	300	46	Sound Mapping - F21
16	4	302	161	Sound Mapping - F22
16	4	304	177	Sound Mapping - F23
16	4	306	169	Sound Mapping - F24
16	4	308	185	Sound Mapping - F25
16	4	310	45	Sound Mapping - F26
16	4	314	84	Sound Mapping - F28
16	4	316	0	Sound Mapping - R1
16	4	318	2	Sound Mapping - R2
16	4	324	65535	Sound Mapping - TRIGGERED

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)