Releases that make a lasting impression on the industry are few and far between, but one that has made a bigger impact than most comes courtesy of Relax Gaming, in the form the Money Train series. First released in 2019, Money Train was well received, but it was Money Train 2 that really kickstarted the journey for this team.
Followed by Money Train 3, a few Money Cart alternatives and a Dream Drop version this train, by admission of Relax Gaming themselves, electrified the industry.
Now, as we leave behind the latest in a different series from this team, Torii Tumble, Relax Gaming are offering us one last chance to climb aboard this train for its final destination, in Money Train 4. Offering ‘more grit than gaming has ever seen', new characters and explosive feature combos, this is one finale that's not to be missed.
With RTP options up to 96.10% (96.50% feature buy), this highly (5/5) volatile release can produce wins up to 150,000x bet.

It's a calmer atmosphere in Money Train 4 than we saw in Money Train 3, with the base game action taking place outside on a sunny day. We're in a desert landscape, with huge stone structures in the background and not a cloud in the sky – although we do see some falling explosions in the distance.
Things get a bit darker during the bonus round, with heavy rain and flaming fires, but for now this is what we see. Does it have as much of an immediate impact as Money Train 3? Maybe not – but the standard of artwork is still far above reproach and sits at the level we expect from this team.
Symbols on the reels consist of the normal characters we're used to (along with a few new ones), whilst skulls, guns and ammunition bring some brutality back into the mix. Finally, a bold and intense soundtrack comes in to tie it all together.

Money Train 4 Base Features
Taking place across 6 reels, wins are formed on Money Train 4 by matching 8 or 10 symbols anywhere on the reels. Symbols pay for 8 (where applicable), 10, 12, 15, 20, 25, 30 or 36 in view, and begin with non premiums – diamonds, clubs, hearts and spades, awarding wins between 0.40 and 0.50x bet for 10 in view, increasing to values between 100 and 125x bet for 36 in view.
Premiums begin with a male and female character, awarding wins of 1 and 1.20x bet for 10 in view, increasing to values between 250 and 400x bet for 36 in view. The 2 highest paying characters are the only to pay for 8 in view, awarding wins of 1 and 1.20x bet, increasing to values of 500 and 1,000x bet for 36 in view.

Respin Feature
There's only one feature available in the base game of Money Train 4, with the majority of the action reserved for the bonus round – the Respin Feature, which is triggered randomly at the end of any spin. Whichever symbol occurs most on the reels will be chosen as the sticky symbol, with all instances stuck into place and 1 respin awarded.
During the respin only sticky symbols or multiplier symbols can land on the reels, with a new respin awarded each time this happens. Multiplier symbols do not stick on the reels but their values are collected above the meter to the lefthand side – which signifies the value won so far according to the number of symbols on the reels.
At the end of the Respin feature, the total win is multiplied by the total value of all collected multipliers.

Money Train 4 Bonus
Land 3 or more Bonus Symbols to trigger the Money Cart Bonus Round, with 3 spins awarded. Once the bonus round starts, all triggering symbols will reveal a value between 1 and 10x bet and stick into place. Each time a new symbol lands in view it will also stick into place, and respins will reset back to 3.
Reels are taller in the bonus round, with 8 rows in total and the usual 6 columns. However, only the middle 4 rows are unlocked at the start of the bonus round, whilst the top 2 and bottom 2 are closed off. All symbols that land behind the closed off rows will also lock into place.
Each time a row is filled with symbols, one additional row will unlock and any symbols that were behind the row will perform their action. This can happen a maximum of 4 times in one bonus round, unlocking all additional rows.
Alongside regular Bonus Symbols, it is possible that Persistent Symbols will land in view. These can substitute for Bonus Symbols when triggering the bonus round, or land during the bonus round. If they land during the trigger, they will perform their action before the first spin. Finally, Feature Symbols can land.
After every spin of the bonus round, the Total Win will update to reflect any new symbols landing, or any changes made to existing symbols through Feature Symbols.

Bonus Round Symbols
The following Bonus, Feature or Persistent Symbols can land in the Money Cart Bonus Round.
- Bonus Symbol – reveals a value between 1 and 10x bet.
- Collector – collects all values on unlocked rows (except its own) and adds the total to its own value.
- Persistent Collector – collects all values on unlocked rows (except its own) and adds the total to its own value at the end of that spin and every spin that follows.
- Adjacent Collector – collects all values on the 8 adjacent positions to its own value.
- Persistent Adjacent Collector – collects all values on the 8 adjacent positions to its own value at the end of that spin and every spin that follows.
- Payer – reveals a value and adds it to the value of all other values on unlocked rows.
- Persistent Payer – reveals a value and adds it to the value of all other values on unlocked rows (except its own) at the end of that spin and every spin that follows.
- Adjacent Payer – reveals a value and adds it to the value of any symbols in the 8 adjacent positions to its own value.
- Persistent Adjacent Payer – reveals a value and adds it to the value of any symbols in the 8 adjacent positions to its own value at the end of that spin and every spin that follows.
- Sniper – doubles the value of 3-8 other Bonus Symbols, with the ability to act on the same Bonus Symbol several times.
- Persistent Sniper – doubles the value of 3-8 other Bonus Symbols, with the ability to act on the same Bonus Symbol several times, at the end of that spin and every spin that follows.
- Collector Payer – selects 3-5 symbols as targets, adds their values to its own value, then adds its updated value back to each of those targets.
- Persistent Collector Payer – selects 3-5 symbols as targets, adds their values to its own value, then adds its updated value back to each of those targets at the end of that spin and every spin that follows. New targets are chosen on each spin, but they may repeat.
- Arms Dealer – converts 1-4 Bonus Symbols into a Feature Symbol, with these symbols performing their new action after conversion.
- Persistent Arms Dealer – converts 1-4 Bonus Symbols into a Feature Symbol at the end of that spin and every spin that follows, with these symbols performing their new action after conversion.
- Necromancer – brings between 2-7 already used Feature Symbols back to life again, with the ability to act on the same Feature Symbol multiple times.
- Persistent Necromancer – brings between 2-7 already used Feature Symbols back to life again at the end of that spin and every spin that follows, with the ability to act on the same Feature Symbol multiple times.
- Persistent Shapeshifter – turns into a Collector, Payer, Sniper, Collector Payer, Arms Dealer or Unlocker after every spin.
- Unlocker – unlocks a locked row.
- Reset Plus – increases the starting value of the spins left counter by +1.
- Upgrader – upgrades 1-3 Feature Symbols into their Persistent Symbol counterpart.

Buy Feature
Players in appropriate regions can skip straight to the action with the following Buy Feature options.
- Original Feature (guaranteed trigger) – 100x bet
- Persistent Feature (guaranteed trigger with 1 Persistent Symbol) – 500x bet
The RTP for both options is 96.50%.
Worth noting is that it is still possible to trigger with a Persistent Symbol when buying the Original Feature – it just is not guaranteed.
The maximum win available in Money Train 4 is 150,000x bet. If the sum of a single game round exceeds this, the game round will end and 150,000x bet will be awarded.

First Impression
Well, talk about going out with a bang. Relax Gaming clearly decided Money Train 4 would be their last, and pulled together all their resources to make it the most intense release so far in this series. The result? 21 possible symbols in the bonus round, with 8 of them being completely new. Let's put a pin in that for a minute though and talk about the base game, where the Respin Feature carries the heavy load.
With symbol payout values ranging between 100 and 1,000x bet for filling the reels and multipliers on offer, the Respin Feature is not quite as tame as it looks at first glance, and is certainly capable of producing potent results.
Now, back to the good bit – the bonus round. The core of this feature hasn't changed – spins reset back to 3 each time a new symbol lands, additional rows (although previously this was additional reels) can be unlocked by filling those that are already there and you're on the lookout for Feature Symbols – in particular Persistent Symbols. Simple.
Similarly to Money Train 3, it's easy to see how symbols like Persistent Collector Payers can produce huge results – with our best creating a win of over 10,000x bet with only one additional 1x bet symbol landing during the bonus round. Snipers, Necromancers and Shapeshifters are all pretty obvious too, but we've now got new symbols, including Adjacent Payers, Adjacent Collectors, and both regular and Persistent Arms Dealers to help transform regular symbols into Feature Symbols – kind of like a new twist on the Shapeshifter, but better.
All this to say, there are one million and one different ways to see impressive results in this one, which makes it all the more exciting for players who aren't just yearning for one set up. When the right combinations occur in any circumstance, wins are possible up to 150,000x bet.
Finally, maths is highly (5/5) volatile, and RTP options are available up to 96.10% (96.50% feature buy), so as always it's worth checking this. What else is there to say? Money Train 4 perfectly finishes the series off, with enough bells and whistles to prove that Relax Gaming are the experts in hold and win releases.
*The screenshots taken of games reviewed on this site are taken from Demo Play, as reviews are often written before games are released for real play.