The TCS WOW121 is a universal WOWSound decoder for HO locomotives with a 21-pin MTC (NEM660) connector. It interfaces through a TCS motherboard, which sets how many lighting functions the install supports and whether they drive LEDs or 1.5V/12V bulbs. This is the Diesel version with TCS's selectable prime-mover sound sets — choose between EMD, Alco, Baldwin/others, and GE engine sounds to match your prototype. Pick a matching speaker from our DCC Accessories collection, browse more DCC Decoders, or shop the full Train Control Systems WOWSound lineup. Features CD-quality WOWSound — 16-bit audio at a 44.1 kHz sample rate. Selectable TCS's selectable prime-mover sound sets choose between EMD, Alco, Baldwin/others, and GE engine sounds to match your prototype. Back-EMF load compensation for superior slow-speed control under load. Quiet Drive super-quiet motor control for buzz-free running. Variable Momentum for custom acceleration and deceleration curves. Audio Assist® menu programming — set up sound and CVs right on the track, no computer required. 21-pin MTC (NEM660) connector — interfaces through a TCS motherboard. More Information Brand Train Control Systems (TCS) Item Number 1527 Decoder WOW121 Type WOWSound DCC Sound Decoder Sound Diesel Connection 21-pin MTC / NEM660 (requires a TCS motherboard) On-board Keep-Alive No Scale HO Scale Condition New FAQ Will this decoder fit my locomotive?The WOW121 is for HO locos with a 21-pin MTC (NEM660) connector and requires a TCS motherboard to interface with the loco and its lighting. Do I need a separate speaker?Yes — this is the decoder only. Add a WOWSpeaker (or any 8 Ω DCC speaker) sized for your locomotive to hear the sound. What is Audio Assist?It's TCS's on-the-fly programming menu that walks you through sound and CV setup using your throttle and the decoder's own spoken prompts — no programming track or computer needed.
$89.99
The TCS WOW121 is a universal WOWSound decoder for HO locomotives with a 21-pin MTC (NEM660) connector. It interfaces through a TCS motherboard, which sets how many lighting functions the install supports and whether they drive LEDs or 1.5V/12V bulbs. This is the Steam version, delivering TCS's authentic steam sound set with synchronized chuff and a full suite of whistle, bell, and running effects. Pick a matching speaker from our DCC Accessories collection, browse more DCC Decoders, or shop the full Train Control Systems WOWSound lineup. Features CD-quality WOWSound — 16-bit audio at a 44.1 kHz sample rate. Authentic TCS's authentic steam sound set with synchronized chuff and a full suite of whistle, bell, and running effects. Back-EMF load compensation for superior slow-speed control under load. Quiet Drive super-quiet motor control for buzz-free running. Variable Momentum for custom acceleration and deceleration curves. Audio Assist® menu programming — set up sound and CVs right on the track, no computer required. 21-pin MTC (NEM660) connector — interfaces through a TCS motherboard. More Information Brand Train Control Systems (TCS) Item Number 1525 Decoder WOW121 Type WOWSound DCC Sound Decoder Sound Steam Connection 21-pin MTC / NEM660 (requires a TCS motherboard) On-board Keep-Alive No Scale HO Scale Condition New FAQ Will this decoder fit my locomotive?The WOW121 is for HO locos with a 21-pin MTC (NEM660) connector and requires a TCS motherboard to interface with the loco and its lighting. Do I need a separate speaker?Yes — this is the decoder only. Add a WOWSpeaker (or any 8 Ω DCC speaker) sized for your locomotive to hear the sound. What is Audio Assist?It's TCS's on-the-fly programming menu that walks you through sound and CV setup using your throttle and the decoder's own spoken prompts — no programming track or computer needed.
$87.99
The Train Control Systems KA4 Keep-Alive® is a compact stay-alive capacitor pack that feeds backup power to your DCC decoder whenever the wheels lose contact with the rails. No more stalling on dirty track, dead frogs, or insulated turnouts — the KA4 keeps a locomotive running with its lights and sound on for roughly 6 to 20 seconds during a power interruption (depending on the locomotive and motor). It includes Blue and Black-with-White-stripe lead wires to solder to your decoder's keep-alive pads (V+ and ground), so it works with TCS and most other-brand decoders that accept an external keep-alive. Browse more decoder add-ons in our DCC Accessories collection, shop the full Train Control Systems lineup, or pair it with a new sound decoder from our DCC Decoders collection. Features Keep-Alive® stay-alive capacitor pack eliminates stalling on dirty track, dead frogs, and insulated rail joints. Powers an HO locomotive with lights on for approximately 6 to 20 seconds during a power interruption. Includes Blue and Black/White lead wires to solder to your decoder's keep-alive pads — works with TCS and most other-brand decoders. Dimensions: .52" x .52" x .45" (13.22 x 13.22 x 11.55 mm). Input rating 12–16V; works with any scale and any DCC system. More Information Brand Train Control Systems (TCS) Item Number 1668 (KA4) Type Keep-Alive / Stay-Alive Capacitor Pack Connection Blue + Black/White Wire Leads (solder-on) Dimensions .52" x .52" x .45" (13.22 x 13.22 x 11.55 mm) Input Rating 12–16V Scale Any Scale Condition New FAQ What does a Keep-Alive actually do?It stores an electrical charge and feeds it to your decoder when track power drops out, so the locomotive keeps moving and its lights and sound stay on across dirty track, frogs, and gaps. How do I connect the KA4?Solder the Blue wire to your decoder's keep-alive positive (V+) pad and the Black/White wire to the ground pad. It works with TCS decoders and most other brands that offer keep-alive connections — check your decoder's manual for the correct pads. How long will it keep my loco running?Expect roughly 6 to 20 seconds with headlights on for a typical HO locomotive, depending on motor efficiency and current draw.
$24.99
The Train Control Systems KA2 Keep-Alive® is a compact stay-alive capacitor pack that feeds backup power to your DCC decoder whenever the wheels lose contact with the rails. No more stalling on dirty track, dead frogs, or insulated turnouts. The KA2 comes in at about half the size of a KA4 and delivers roughly one-third the capacitance of a KA3/KA4, making it a great choice where space is tight in N and smaller HO locomotives. It includes Blue and Black-with-White-stripe lead wires to solder to your decoder's keep-alive pads (V+ and ground), so it works with TCS and most other-brand decoders that accept an external keep-alive. Browse more decoder add-ons in our DCC Accessories collection, shop the full Train Control Systems lineup, or pair it with a new sound decoder from our DCC Decoders collection. Features Keep-Alive® stay-alive capacitor pack eliminates stalling on dirty track, dead frogs, and insulated rail joints. Compact — about half the size of a KA4; delivers roughly one-third the capacitance of a KA3/KA4. Includes Blue and Black/White lead wires to solder to your decoder's keep-alive pads — works with TCS and most other-brand decoders. Dimensions: 0.35" x 0.35" x 0.61" (8.9 x 8.9 x 15.5 mm). Input rating 12–16V; works with any scale and any DCC system. More Information Brand Train Control Systems (TCS) Item Number 1456 (KA2) Type Keep-Alive / Stay-Alive Capacitor Pack Connection Blue + Black/White Wire Leads (solder-on) Dimensions 0.35" x 0.35" x 0.61" (8.9 x 8.9 x 15.5 mm) Input Rating 12–16V Scale Any Scale Condition New FAQ What does a Keep-Alive actually do?It stores an electrical charge and feeds it to your decoder when track power drops out, so the locomotive keeps moving and its lights and sound stay on across dirty track, frogs, and gaps. How do I connect the KA2?Solder the Blue wire to your decoder's keep-alive positive (V+) pad and the Black/White wire to the ground pad. It works with TCS decoders and most other brands that offer keep-alive connections — check your decoder's manual for the correct pads. Why choose the KA2 over a larger KA3/KA4?It's much smaller and fits where bigger packs won't — ideal for N scale and cramped HO shells. It holds less charge, so for longer run-through use a KA3 or KA4 if you have the room.
$24.99
The Train Control Systems KA4-P Keep-Alive® is a compact stay-alive capacitor pack that feeds backup power to your DCC decoder whenever the wheels lose contact with the rails. No more stalling on dirty track, dead frogs, or insulated turnouts — the KA4-P keeps a locomotive running with its lights and sound on for roughly 6 to 20 seconds during a power interruption, depending on the locomotive and motor efficiency. This is the harness-equipped version: it ships with a 2-Pin Quick Connector Harness that plugs straight into any decoder with a compatible 2-pin Keep-Alive socket, such as the TCS T4 and other current TCS decoders — no soldering to the decoder required. Electrically it works in any scale, and its tiny .52" footprint tucks easily into HO and larger locomotives. Browse more decoder add-ons in our DCC Accessories collection, shop the full Train Control Systems lineup, or pair it with a new sound decoder from our DCC Decoders collection. Features Keep-Alive® stay-alive capacitor pack eliminates stalling on dirty track, dead frogs, and insulated rail joints. Powers an HO locomotive with headlights on for approximately 6–20 seconds during a power interruption. Includes a 2-Pin Quick Connector Harness — plugs into the TCS T4 and other decoders with a compatible 2-pin socket, no decoder soldering needed. Ultra-compact: just .52" x .52" x .45" (13.22 x 13.22 x 11.55 mm) — fits HO and larger locomotives. Works with any scale and any DCC system; pairs with TCS and most other-brand decoders that accept an external keep-alive. More Information Brand Train Control Systems (TCS) Item Number 2005 (KA4-P) Type Keep-Alive / Stay-Alive Capacitor Pack Connection 2-Pin Quick Connector Harness Dimensions .52" x .52" x .45" (13.22 x 13.22 x 11.55 mm) Hold-Up Time ~6–20 sec (HO, lights on) Scale Any Scale (HO and larger recommended) Condition New UPC 879508007848 FAQ What does a Keep-Alive actually do?It stores an electrical charge and feeds it to your decoder when track power drops out, so the locomotive keeps moving and its lights and sound stay on across dirty track, frogs, and gaps. Will the KA4-P plug into my decoder?The included 2-pin harness plugs into TCS decoders with a compatible Keep-Alive socket (such as the T4) and most current TCS decoders. For decoders without a 2-pin socket, you can solder the leads to the decoder's keep-alive pads — check your decoder's manual first. What scales can use it?Electrically it works in any scale. Its small size suits HO and larger; in N scale it fits wherever there is room in the shell or tender. How long will it keep my loco running?Expect roughly 6 to 20 seconds with headlights on for a typical HO locomotive, depending on motor efficiency and current draw.
$26.99
The TCS WDK-ATL-1 WOWKit is a complete, drop-in WOWSound installation engineered to fit a specific Atlas HO locomotive. Everything you need comes in the box, so even a first-time DCC installer can get clean, professional sound without guesswork. Each kit includes a WOWSound decoder, a TCS motherboard with on-board Keep-Alive® for stutter-free running, a speaker with speaker wire and enclosure, and a motor mounting clip. The decoder carries TCS's selectable diesel prime-mover sound sets — EMD, Alco, Baldwin/others, and GE — so you can match the engine to your prototype. Need a stand-alone decoder or speaker instead? Browse our DCC Decoders and DCC Accessories, or shop the full Train Control Systems WOWSound lineup. Features Complete drop-in sound kit engineered to fit a specific Atlas HO locomotive. Includes a WOWSound decoder, TCS motherboard with on-board Keep-Alive®, a speaker with speaker wire and enclosure, and a motor mounting clip. CD-quality WOWSound — 16-bit audio at 44.1 kHz with selectable EMD, Alco, Baldwin/others, and GE diesel sound sets. Back-EMF load compensation and Quiet Drive for smooth, silent slow-speed control. Audio Assist® menu programming — set up sound and CVs right on the track, no computer needed. More Information Brand Train Control Systems (TCS) Item Number 1775 (WDK-ATL-1) Type WOWKit — Complete WOWSound Install Kit Fits Specific Atlas HO locomotive (see TCS WOWKit application chart) Includes WOWSound decoder, motherboard w/ Keep-Alive, speaker, motor clip Sound Diesel (EMD / Alco / Baldwin / GE selectable) Scale HO Scale Condition New FAQ What comes in the kit?Everything for a complete sound install: a WOWSound decoder, a TCS motherboard with on-board Keep-Alive, a correctly-sized speaker, and a motor mounting clip — all engineered to fit the target locomotive. Will it fit my locomotive?WOWKits are model-specific. This WDK-ATL-1 kit is matched to a particular Atlas HO engine — confirm your exact model against the TCS WOWKit application chart before ordering, or reach out and we'll help you check. Do I need any other parts?No — the kit is self-contained. You'll just need basic install tools and a soldering iron for the speaker leads.
$144.95 $117.95
The TCS WDK-ATL-3 WOWKit is a complete, drop-in WOWSound installation engineered to fit a specific Atlas HO locomotive. Everything you need comes in the box, so even a first-time DCC installer can get clean, professional sound without guesswork. Each kit includes a WOWSound decoder, a TCS motherboard with on-board Keep-Alive® for stutter-free running, a speaker with speaker wire and enclosure, and a motor mounting clip. The decoder carries TCS's selectable diesel prime-mover sound sets — EMD, Alco, Baldwin/others, and GE — so you can match the engine to your prototype. Need a stand-alone decoder or speaker instead? Browse our DCC Decoders and DCC Accessories, or shop the full Train Control Systems WOWSound lineup. Features Complete drop-in sound kit engineered to fit a specific Atlas HO locomotive. Includes a WOWSound decoder, TCS motherboard with on-board Keep-Alive®, a speaker with speaker wire and enclosure, and a motor mounting clip. CD-quality WOWSound — 16-bit audio at 44.1 kHz with selectable EMD, Alco, Baldwin/others, and GE diesel sound sets. Back-EMF load compensation and Quiet Drive for smooth, silent slow-speed control. Audio Assist® menu programming — set up sound and CVs right on the track, no computer needed. More Information Brand Train Control Systems (TCS) Item Number 1773 (WDK-ATL-3) Type WOWKit — Complete WOWSound Install Kit Fits Specific Atlas HO locomotive (see TCS WOWKit application chart) Includes WOWSound decoder, motherboard w/ Keep-Alive, speaker, motor clip Sound Diesel (EMD / Alco / Baldwin / GE selectable) Scale HO Scale Condition New FAQ What comes in the kit?Everything for a complete sound install: a WOWSound decoder, a TCS motherboard with on-board Keep-Alive, a correctly-sized speaker, and a motor mounting clip — all engineered to fit the target locomotive. Will it fit my locomotive?WOWKits are model-specific. This WDK-ATL-3 kit is matched to a particular Atlas HO engine — confirm your exact model against the TCS WOWKit application chart before ordering, or reach out and we'll help you check. Do I need any other parts?No — the kit is self-contained. You'll just need basic install tools and a soldering iron for the speaker leads.
$104.95
The TCS A6 is a six-function HO-scale "drop-in" DCC mobile decoder with an integrated 1.5V power supply, designed to replace the factory light board in many popular Atlas, Athearn, and Kato diesels. Examples include the Athearn F59PHI and F3; Atlas RS-1, RS-3, RS-11, C424, and GP7; and the Kato GP35. Browse more DCC Decoders and DCC Accessories, or shop the full Train Control Systems lineup. Features Six-function HO drop-in mobile decoder — replaces the factory light board on supported Atlas, Athearn, and Kato diesels. Integrated 1.5V power supply for running 1.5V bulbs directly. Back-EMF load compensation for superior slow-speed control under load. Quiet Drive super-quiet motor control for buzz-free running. No-solder installation on supported drop-in locomotives. More Information Brand Train Control Systems (TCS) Item Number 1001 (A6) Type DCC Mobile Decoder (drop-in) Functions 6 1.5V Supply Yes (integrated) Fits Many Atlas / Athearn / Kato HO diesels Scale HO Scale Condition New FAQ Will it fit my locomotive?The A6X drops into many Atlas, Athearn, and Kato HO diesels (for example Athearn F59PHI/F3; Atlas RS-1/RS-3/RS-11/C424/GP7; Kato GP35). Check the TCS drop-in chart for your exact model. Does it include sound?No — the A6X is a motor and function (mobile) decoder, not a sound decoder. For sound, see the TCS WOW series. A6X or A4X?Choose the A6 for up to six functions or the integrated 1.5V bulb supply; the A4X covers four-function installs.
$36.99
