Relax Gaming went from being an aggregation platform that distributed other studios’ games to being one of the most talked-about slot developers in the UK market. The pivot happened in 2019 when Money Train launched and the Money Cart Bonus mechanic — persistent symbols that interact with each other across respins — produced the kind of unpredictable, escalating bonus sessions that streaming communities thrive on. Money Train 2 (2020) then became one of the most-streamed UK slots ever made. Three sequels later, Money Train 4 has a 150,000× maximum win and 21 modifiers in the bonus round.
Relax Gaming also has Book of 99 — a 99% RTP slot that has no business existing in a commercial context but does. And they still run the Silver Bullet and Powered By Relax distribution platforms that host games from BTG, Quickspin, Nolimit City, and others. They’re a genuine hybrid: distribution infrastructure company that accidentally became a leading original content studio.
Variable RTP note upfront: Relax Gaming offers multiple RTP configurations per game. Money Train 4’s range is 94%–96.1%. The lower variant is 2.1 percentage points below standard — meaningful across extended high-stakes sessions. Always verify the in-game RTP before playing Money Train titles.
Relax Gaming — Provider Snapshot
| Category | Detail |
|---|---|
| Founded | 2010, Malta |
| Business model | Dual: in-house game development + B2B aggregation platform (Silver Bullet / Powered By Relax) |
| UKGC Licence | Yes |
| MGA Licence | Yes |
| In-house catalogue | 100+ games |
| Platform catalogue | Hundreds of additional games from partner studios (BTG, Quickspin, Nolimit City, and others) |
| Variable RTP | Yes — typically 94% and 96%+ versions available; verify in-game |
| Portfolio average RTP | ~96%+ (standard configurations); lower on jackpot variants |
| Typical volatility | High to Very High (Money Train series is 5/5 volatility) |
| Signature mechanic | Money Cart Bonus — persistent special symbols (Collectors, Payers, Snipers, Necromancers) interacting across respins on an expanding grid |
| Key franchises | Money Train series (1–4), Money Cart series, Dream Drop jackpot network |
| UK restriction | Bonus buy banned (UKGC). Money Cart as triggered feature remains available; buy entry removed. |
| UK casino availability | Major UK operators — Casumo, 10Bet, Ladbrokes carry Money Train series |
The Money Cart Bonus — The Mechanic That Built Relax Gaming’s Reputation
To understand Relax Gaming, you need to understand the Money Cart Bonus. It’s not a standard free spins round. It’s a respin system where special symbols with distinct interactions fill a grid, and the interactions between those symbols determine the win.
How the base mechanic works: Landing three scatter symbols triggers the Money Cart Bonus. You receive 3 respins on a separate grid. Only special symbols and multiplier values can land — no standard paying symbols. Each time a new special symbol lands, the respin count resets to 3. The bonus continues until you exhaust all respins without a new symbol landing, or you fill the entire grid.
The symbol types and their interactions:
- Payer — displays a multiplier value. Counted at the end of the bonus.
- Collector — collects the values of all Payer symbols visible on the grid simultaneously and adds them to its own value. One Collector landing next to multiple high-value Payers can produce a single symbol worth hundreds of times stake.
- Sniper — doubles the value of a random symbol. Can fire multiple times.
- Necromancer — brings previously expired symbols back to life for additional respin activations.
- Persistent symbols (later games) — stay active across every remaining respin rather than being collected once. A Persistent Collector collects from every new Payer that lands for the rest of the feature.
- Widener — expands the grid by adding a new reel, creating more positions for subsequent symbols to fill.
The key dynamic: the mechanic is multiplicative, not additive. A Collector landing on a grid with four Payers worth 50×, 80×, 120×, and 200× doesn’t give you their sum (450×). It gives the Collector a value of 450×, which then becomes the Collector’s new displayed value. If a Sniper then doubles that Collector, it becomes 900×. If a second Collector then lands and collects the first Collector’s value… you can see where this goes.
This symbol interaction system is what produces the Money Train series’ extreme win sessions and why it dominates streaming content. A single well-populated bonus can escalate faster than any free spins multiplier system, because each new symbol increases the value of all previous symbols retroactively. The downside: the exact same mechanic means completely empty bonuses (3 respins, one symbol, done) are equally possible. Very high volatility is not a description — it’s a warning.
The Money Train Series — All Four Games
| Game | Released | RTP (standard) | Max Win | Grid | Key addition vs previous |
|---|---|---|---|---|---|
| Money Train | 2019 | 96.20% | 20,000× | 5×4, 40 paylines | Original Money Cart Bonus — Collectors, Payers, Sniper, Widener |
| Money Train 2 | 2020 | 96.40% | 50,000× | 5×4, 40 paylines | Necromancer; Persistent Sniper; base game Respin feature on 2 bonus symbols |
| Money Train 3 | 2022 | 96.00% | 100,000× | 5×4 base, expanded bonus | Tommy Gun Sniper (doubles random symbol up to 6× over multiple fires); Absorber; Persistent versions of all symbols |
| Money Train 4 | Sept 2023 | 96.10% | 150,000× | 6×6 scatter pays | 21 modifiers in Money Cart; scatter pays (no paylines); expanded grid; futuristic dystopian visual overhaul |
Money Train (2019) — The Original
| Stat | Detail |
|---|---|
| RTP | 96.20% (standard) — verify before playing |
| Volatility | Very High (5/5) |
| Max Win | 20,000× stake |
| Hit frequency | 18.73% (approximately 1 win per 5.3 spins) |
| Min Bet | 10p |
The game that started it. The base Money Cart Bonus with Collectors, Payers, Sniper, and Widener in their original form — cleanest expression of the mechanic before subsequent games added layers of complexity. For players new to the Money Train series, starting with the original is the correct approach: understand how Collectors and Payers interact, how the Widener extends the grid, how a full grid win is calculated, before progressing to Money Train 2’s added symbol types.
Budget 150–200× your stake per session. Very high volatility at 5/5 means extended base game sequences without bonus triggers are entirely routine.
Money Train 2 (2020) — The Cultural Peak
| Stat | Detail |
|---|---|
| RTP | 96.40% (standard) — highest RTP in the series |
| Volatility | Very High (5/5) |
| Max Win | 50,000× stake |
| Min Bet | 20p |
Money Train 2 is the series highpoint in terms of cultural impact — the most-streamed, most-discussed, and for many players the most memorable Relax Gaming game ever made. The 96.40% RTP is the best in the series. The Necromancer symbol (resurrects expired symbols back to active status for up to seven more respins) and Persistent Sniper (applies its doubling effect repeatedly across remaining respins rather than once) take the original’s symbol interaction system to a higher ceiling.
A Persistent Sniper combined with a Necromancer-revived high-value Collector is the Money Train 2 holy grail — the interaction produces compound multiplications that can drive wins toward the 50,000× ceiling in a single well-constructed bonus. These moments are rare. When they happen, they’re unlike anything available in a standard free spins game.
Money Train 2 is the recommended entry point for players who’ve already played the original and understand the base mechanic.
Money Train 4 (2023) — The Series Finale
| Stat | Detail |
|---|---|
| RTP | 96.10% (standard); 94% lower variant available — verify in-game |
| Volatility | Very High (5/5) |
| Max Win | 150,000× stake — highest in the series; among the highest of any standard UK slot |
| Grid | 6×6 scatter pays (no paylines; wins from 8+ of highest symbols or 10+ of others appearing anywhere) |
| Modifiers | 21 in the Money Cart Bonus |
| Hit frequency | 20.14% |
| Min Bet | 10p |
Money Train 4: The Last Stand is the series conclusion and its most ambitious game. The shift from 5×4 payline grid to 6×6 scatter pays changes the base game feel significantly — wins now come from matching symbols appearing anywhere on the expanded grid rather than from left-to-right payline combinations. This produces different session rhythm: cluster accumulation rather than payline evaluation.
The 21 modifiers in the Money Cart Bonus represent the full evolution of the symbol system across all four games. Persistent versions of every symbol type, expanded grid mechanics, and new interactions between modifier categories create a bonus round that can theoretically run almost indefinitely on a grid-filling scenario — and when the symbol interactions compound across a full 6×6 grid, the path to the 150,000× ceiling becomes mechanically visible (rare, but not purely theoretical).
At 96.10% standard RTP — slightly lower than Money Train 2’s 96.40% — the mathematical trade-off for the higher ceiling is clear. For players who have played through the series: Money Train 4 is the logical conclusion. For new players: start with Money Train or Money Train 2 to understand the mechanic before the complexity of 21 modifiers.
Book of 99 — The 99% RTP Game
| Stat | Detail |
|---|---|
| RTP | 99.00% |
| Volatility | High |
| Max Win | 12,075× per free spins round |
| Grid | 5 reels × 3 rows, 10 paylines |
| Released | 2021 |
| Key mechanic | Special Expanding Symbol during free spins (same as Book of Dead structure); 99 Book Wild/Scatter collection alternative trigger |
Book of 99 has a 99% RTP — the highest of any standard slot available at UK-licensed casinos, matching Mega Joker (NetEnt) in Supermeter mode and exceeding Blood Suckers (NetEnt) at 98%.
The name is literal: 99% RTP. The structure is familiar — it follows the “Book of” mechanic popularised by Book of Dead, with an expanding symbol during free spins. What’s unusual is the alternative trigger: collecting 99 Book Wild/Scatter symbols in the base game triggers free spins without needing to land 3 scatters simultaneously. This collection mechanic reduces the pure-luck dependency of the bonus trigger.
At 99% RTP, Book of 99 is mathematically the most player-friendly slot on this list. The expected loss per £100 wagered is £1 — compared to £4 at the industry standard 96% RTP. For extended sessions, bonus clearing, or any situation where minimising expected losses is the priority, Book of 99 is the strongest option available from any major provider.
Important: verify the specific RTP at your casino before extended play. Relax Gaming offers lower RTP configurations, and Book of 99 should theoretically also have reduced variants at some operators. Check the game information screen — if it shows anything below 99%, you’re not getting the game’s defining feature.
The Money Cart Series — UK-Specific Spin-Offs
Relax Gaming created the Money Cart series specifically for markets without bonus buy (including the UK). Money Cart effectively drops players directly into the Money Cart Bonus mechanic with each spin functioning as a bonus round entry — a different session experience from Money Train’s base-game-then-bonus structure.
Money Cart 2 and Money Cart 3 expand this approach. For UK players who want the Money Cart Bonus experience without the extended base game wait between triggers (which is the primary appeal of bonus buy internationally), the Money Cart series is designed for that purpose. The RTP and max win profiles are broadly similar to the corresponding Money Train games.
Relax Gaming as an Aggregation Platform
Beyond their own games, Relax Gaming’s Silver Bullet and Powered By Relax platforms distribute content from 30+ partner studios. This means casinos integrating Relax also access BTG’s Megaways catalogue, Quickspin, Nolimit City (covered separately), and many independent studios.
For players, this matters at the casino selection stage: a casino with Relax Gaming integration often has broader access to third-party content than a casino with only direct provider agreements. It’s not a game selection decision (you play specific games regardless), but it explains why some casinos have dramatically deeper catalogues than others.
Honest Assessment
Where Relax Gaming genuinely excels:
- The Money Cart Bonus mechanic is the most original proprietary slot mechanic created since Megaways — symbol interaction systems that produce compound rather than additive wins are genuinely different from everything else in the market
- Book of 99 at 99% RTP is the best standard-slot RTP available at any UK casino — if high RTP is your priority for any session, this is the answer
- The Money Train series represents a coherent four-game evolution narrative that no other franchise has matched — each game builds on the previous one’s mechanic foundation
- Very high volatility executed at the highest quality — the Money Train series is genuinely the best implementation of extreme variance slots in the UK market
Where Relax Gaming has limitations:
- Variable RTP — Money Train 4 runs at 94% at some operators (vs 96.1% standard). The 2.1% gap is real. Always check in-game RTP before Money Train sessions.
- Bonus buy banned in UK — the Money Train games internationally offer bonus buy for direct Money Cart Bonus access. UK players must trigger naturally. The Money Cart spin-off series partially addresses this, but it’s a meaningful product difference from international markets.
- The Money Cart Bonus can produce empty sessions as frequently as extraordinary ones — the 5/5 volatility rating is accurate and demanding. Bankroll requirements are among the highest of any standard slot series.
- Outside the Money Train/Money Cart franchise and Book of 99, Relax’s broader catalogue doesn’t have the same cultural traction. Temple Tumble, TNT Tumble, and other titles are solid but not must-plays.
Frequently Asked Questions — Relax Gaming
What is the Money Cart Bonus and how does it work?
The Money Cart Bonus is triggered by landing three scatter symbols in the base game of any Money Train title. It begins with 3 respins on a separate grid where only special symbols and multiplier values can land. Each new symbol resets the respin count to 3. The bonus ends when respins exhaust without a new landing, or when the grid fills completely. Special symbols — Collectors (absorb all Payer values simultaneously), Payers (display a multiplier value), Snipers (double random symbol values), Necromancers (resurrect expired symbols), and Persistent versions of each — interact with each other. A Collector landing next to multiple Payers collects all their values. A Sniper doubling a Collector then doubles that collected value. These interactions are multiplicative, not additive, which is why the bonus can produce extraordinary wins when symbols align — and empty sessions when they don’t.
What order should I play the Money Train series?
In release order: Money Train (2019) → Money Train 2 (2020) → Money Train 3 (2022) → Money Train 4 (2023). Money Train establishes the base mechanic. Money Train 2 adds Necromancer and Persistent Sniper — the version that made the series famous. Money Train 3 adds Tommy Gun Sniper and Absorber. Money Train 4 switches to a 6×6 scatter pays grid with 21 modifiers. Start with the original to understand symbol interactions before the complexity of later games. Money Train 2 is the best balance of mechanic depth and accessibility. Money Train 4 is for players who fully understand the system and want the highest ceiling (150,000×).
What is Book of 99 and why is the RTP so high?
Book of 99 is a Relax Gaming slot with a 99% RTP — the highest published RTP of any standard (non-Supermeter) slot available at most UK casinos. The name is literal. The 99% figure means an expected loss of £1 per £100 wagered, compared to £4 at the industry standard 96%. The mechanics follow the “Book of” structure popularised by Book of Dead — an expanding special symbol during free spins — with an additional collection-based alternative trigger (99 scatter symbols in the base game). The high RTP makes it mathematically optimal for extended sessions and bonus wagering clearance. Always verify the in-game RTP — reduced variants may exist at some operators.
What is Money Train 4’s maximum win?
Money Train 4’s maximum win is 150,000× stake — the highest in the Money Train series and one of the highest of any standard (non-progressive) slot available at UK casinos. At the 10p minimum bet, that’s a theoretical maximum of £15,000. At £1/spin, £150,000. The 150,000× ceiling is accessible through the 6×6 grid filling with interacting Persistent symbols and compound Collector-Payer-Sniper combinations in the Money Cart Bonus. It’s rare but mechanically grounded — not a theoretical maximum that requires impossible symbol distributions. The game’s 5/5 volatility rating and 20.14% hit frequency in the base game are the context for how infrequently the extreme ceiling sessions occur.
Does Relax Gaming have variable RTP?
Yes. Relax Gaming offers multiple RTP configurations per game. Money Train 4’s range is 94%–96.1%. The lower 94% variant is 2.1 percentage points below standard — equivalent to an additional £2.10 expected loss per £100 wagered vs the standard version. Always check the RTP displayed in the game’s information screen before Money Train sessions, particularly at smaller operators. Major UK operators in our sidebar generally run standard or near-standard configurations.
Can I use bonus buy on Money Train in the UK?
No. Bonus buy (direct Money Cart Bonus purchase) is banned at all UK-licensed casinos following the UKGC ruling in October 2021. All Money Train games internationally offer a bonus buy feature; UK players must trigger the Money Cart Bonus through natural gameplay (landing 3 scatter symbols). Relax Gaming created the Money Cart spin-off series specifically for markets without bonus buy — Money Cart, Money Cart 2, and Money Cart 3 are structured so each spin functions more directly within the bonus mechanic, addressing the inability to buy direct access.
