# OTOTETSU vs 6uo

OTOTETSU and 6uo are too close to call on the numbers: across 6 compared parameters — price, update cadence, ads and in-app purchases among them — neither pulls far enough ahead to decide it. What separates them is feature set and interface, not measurable difference.

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

OTOTETSU ships an update every 2 months, 6uo monthly. The most recent releases landed on October 22, 2026 and October 6, 2026 respectively.

## The numbers

| Metric | OTOTETSU | 6uo |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.7 (19 ratings)](https://appshunter.io/ios/app/ototetsu/id1557885726/reviews)** | — |
| Number of ratings | **19** | — |
| Positive reviews | 93.1% of reviews | — |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 2 months | **Monthly** |
| Monetization | Free | — |
| Size | 20 MB | 27 MB |
| Requires iOS | **15.0** | 15.1 |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Hisato Takeuchi](https://appshunter.io/developer/1512764876) | [6uo Games](https://appshunter.io/developer/1712049504) |

## What reviewers say

### OTOTETSU

[App page](https://appshunter.io/ios/app/ototetsu/id1557885726)

This app simulates the characteristic sounds of electric trains, generated by inverters controlling motor torque and speed. Users can design sounds for imaginary trains by manipulating waveforms and motor sounds.

**Highlights:** Simulates electric train acceleration/deceleration sounds, Generates waveforms from inverters, Simulates motor sounds, Design imaginary train sounds, Customize torque and rotational speed effects

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases:** none


### 6uo

[App page](https://appshunter.io/ios/app/6uo/id6469476100)

**In-app purchases:** none


## Frequently asked questions

### Is OTOTETSU free?

OTOTETSU is free to download, with no in-app purchases.

### Is 6uo free?

6uo is free to download, with no in-app purchases.

### Do OTOTETSU or 6uo have ads?

Neither OTOTETSU nor 6uo shows ads.

### Which is updated more often, OTOTETSU or 6uo?

OTOTETSU ships an update every 2 months, and 6uo monthly. Most recently, OTOTETSU was updated on October 22, 2026 and 6uo on October 6, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*