Money Train 4 Slot by Relax Gaming

The Last Money Train Leaves the Station

Money Train 4 wraps up Relax Gaming's flagship series with the biggest numbers and the most complex bonus round the franchise has seen. A 150,000x max win cap. Twenty-one different modifier types in the Money Cart bonus. An expanding grid that grows from 6x4 to 6x8 mid-round. Someone hit that full 150,000x shortly after launch - a Persistent Collector and Sniper combo that snowballed past 25,000x and slammed into the ceiling.

The series started as a straightforward Western slot in 2019. By the fourth entry, the setting has shifted to a post-apocalyptic alien wasteland with steampunk weaponry and a train armed to the teeth. Each sequel added more modifiers, a bigger grid, and a higher win cap. Money Train 4 is where that escalation peaks.

Base Game: Scatter Pays and Respins

The 6x6 grid uses scatter pays instead of traditional paylines. Eight or more matching symbols anywhere on the reels trigger a win for the two highest-paying characters. Every other symbol needs ten or more. A full grid of 36 matching symbols pays 1,000x for the top character and 100x for the lowest card suit.

The Respin feature fires at the end of any spin. Whichever symbol appears the most gets locked in place and you get a respin. Land more of that symbol or a multiplier symbol, and the respins keep going. Multipliers add together and apply to the final win. It's not flashy, but it breaks up what would otherwise be a dull base game - because the base game is dull. About 80% of spins produce nothing (20.14% hit frequency), and the paytable rewards favor massive clusters that rarely form naturally.

The Paytable Math

Small clusters pay poorly. Ten matching low symbols return 0.4x to 0.5x bet. You need 20+ symbols of a single type to see anything interesting, and at that point the respin feature is doing the heavy lifting. The top symbol (H1) at 36 matches pays 1,000x, but filling an entire 6x6 grid with one symbol type through respins is the kind of thing you see once in a few thousand sessions.

Money Cart Bonus Round

Three or more Bonus symbols (skull icons) trigger the Money Cart. Gold persistent symbols count toward the trigger and act before the first spin. The bonus starts on a 6x4 grid with 3 spins. Every new symbol resets the counter to 3. Fill an entire row and an additional row unlocks - up to four times, maxing at 6x8 (48 positions).

Each Bonus symbol that lands reveals a 1x to 10x value. That's the foundation. The modifiers are what turn those small values into six-figure multipliers.

21 Modifiers - The Full Arsenal

The modifier list reads like a strategy game's tech tree. Collectors grab values from the board and stack them onto themselves. Payers distribute their value to every other symbol on screen. Snipers double 3-8 random symbols (and they target the same one repeatedly). Collector-Payers do both - pull values in, then push the total back out to 3-5 targets.

Each of these comes in a Persistent variant that repeats its action every single spin until the round ends. A Persistent Sniper doubling values each turn creates exponential growth. A Persistent Collector absorbing the board's total and compounding it turn after turn is how you climb from 500x to 50,000x in a handful of spins.

Then there's the Arms Dealer (converts basic symbols into feature symbols), the Necromancer (revives spent non-persistent modifiers), the Upgrader (turns regular modifiers into Persistent ones), and the Persistent Shapeshifter (becomes a different modifier after every spin). The Reset Plus bumps the starting spin count by one permanently. The Unlocker opens a locked row without needing to fill one.

Interactions between modifiers cascade. An Arms Dealer converts a basic symbol into a Collector, which immediately collects the board. A Necromancer revives a spent Sniper, which doubles three more symbols. An Upgrader turns that Sniper into a Persistent Sniper. That's how runs snowball from modest to absurd.

Buying In

Two buy options. The Original Feature costs 100x bet and triggers the Money Cart with the same conditions as a natural trigger. The Persistent Feature costs 500x bet and guarantees one Persistent symbol at the start. Buy feature RTP bumps to 96.50% from the base game's 96.10%.

That 500x buy is steep. At a $2 bet, you're spending $1,000 for one bonus round. But Persistent symbols are what separate a forgettable 200x round from a round that spirals into five figures. Whether that premium is justified depends on how much you value the starting setup versus the natural lottery of triggering modifiers organically.

The Base Game Problem

Money Train 4 is a bonus game with a base game attached. Four out of five spins return nothing. The respin feature adds some life, but most sessions feel like you're feeding the machine and waiting for skulls to appear. Relax Gaming knows this - the buy button is right there, and at 100x it's not even expensive by modern standards. The entire game is designed around the Money Cart round, and everything else is just the door you walk through to get there.