# D51: Steam Locomotive Sim — Authentic Steam Locomotive Sim

> Authentic Steam Locomotive Sim (iPhone/iPad app by Masato Furushima.)

- Source: https://appshunter.io/ios/app/d51-steam-locomotive-sim/id6816905566 (this page in markdown: same URL + `.md`)
- Developer: [Masato Furushima](https://appshunter.io/developer/6792693256)
- Category: Games, Simulation
- Price: $2.99 with in-app purchases
- Age rating: 4+
- Requires: iOS 17.0 · 2 MB
- Languages: American English, Japanese
- Released: 2026-10-03
- Data updated: 2026-10-29

## What is D51?

Manage steam. Drive the D51.
Work the regulator and reverser, maintain boiler pressure and control wheel slip. A steam locomotive simulator for iPhone and iPad.

The base app includes D51 driving conditions, the old Karikachi line, a departure tutorial and run reviews. C62 and C12 are an optional expansion.

DRIVE BY INSTRUMENTS AND SOUND
Read speed, boiler and steam-chest pressure, and steam generation and use. Turn the central reverser handle with your finger, or tap and hold the plus/minus buttons. Operate the regulator, brake, cylinder drains, bypass valve, sand and whistle.
Exhaust follows wheel rotation and steam conditions. Rail-joint sounds follow distance traveled. Whistle strength changes with press depth, and pressure in the steam chest falls as residual steam escapes after the regulator closes.

WATCH THE MACHINERY
Driving wheels, rods and schematic Walschaerts valve gear move with the run. Tap the cylinder to watch valves, pistons, the four chamber pressures and water quantities while driving. See drain steam, discharged water and sand falling toward the wheels.

CHOOSE YOUR CONDITIONS
Choose light-engine, passenger or freight loads, gradients, starting position, weather, temperature and fireman skill. Water, coal and sand are finite. Heavy trains, rain and cold change the challenge.
The fireman handles firing and feedwater, anticipating upcoming gradients and steam demand over a range suited to the selected skill. Drive the 10 km climb from Shintoku on the old Karikachi line, with current and upcoming gradients and distance to the endpoint shown in the cab.

LEARN AND REVIEW
Use the departure tutorial and illustrated operating guide. Read about historical steam-locomotive departure, power, coasting, resuming power, slip, gradients, braking and the fireman's work.
Pause in State to inspect values and graphs. End a run to review train and wheel speed curves, statistics and advice based on your controls.

C62 & C12 EXPANSION PACK (ONE-TIME IN-APP PURCHASE)
One purchase adds C62 driving, C12 driving and C12 yard shunting. D51 remains available without the additional purchase.
Wheels, cylinders, mass, inventories, loads and guide text vary by locomotive.
C62 includes 26.34 km from Tsuchiura to Toride on the Joban Line, based on Tokyo Railway Bureau records. Pass intermediate stations and manage gradients, speed and remaining distance to stop at Toride. A gradient diagram and section guidance are included.
Drive short trains with the C12 tank engine or shunt in an original fictional yard. Use the map to set points and couple or uncouple, then return to the cab to move vehicles. A close view shows the couplers during approach. Attached vehicle weight affects the run. Purchased access can be restored.

No ads or app account registration. Driving and in-app reading work offline. Purchases, restoration, external sources and support pages need an internet connection.

iOS/iPadOS 17+. Landscape on iPhone and both iPhone Duo displays; portrait and landscape on iPad. English and Japanese UI.

Valve motion, thermal, adhesion and locomotive-performance models include approximations. Train weights are representative. Karikachi and Joban use historical gradient records, approximate boundaries and no curve resistance. Scenery, station facilities, signals and timetables are not included. This app is not for operator training or real-world performance calculations.

## Pricing and in-app purchases

Base price: $2.99.

**One-time purchases**

| Purchase | Price | Type |
| --- | --- | --- |
| C62 & C12 Expansion Pack | $2.99 | one-time |


## Is D51 safe?

Not enough ratings yet to assess D51.

## Is D51 legit?

D51: Steam Locomotive Sim appears legitimate, with a few gaps. The AppsHunter Legitimacy Score for D51 is 65 out of 100 points across 7 verification signals from App Store and developer data.


## Version history (last 5 releases)

### 1.2.0 — 2026-10-26

Version 1.2.0 adds rail-joint sounds and updates the cab controls, fireman responses, and train choices.

• Rail-joint sounds follow distance traveled and each axle crossing, so you can hear the rhythm of the wheels while coasting. We also adjusted C12 exhaust.
• Clearer instruments and readouts include a central reverser handle you can turn directly. Acceleration is shown in km/h/s, and grades and distances are easier to read.
• Sanding now uses an on/off toggle. We also revised braking strength and made operation sounds quieter.
• Each locomotive offers six train choices, including light engine. Compare D51, C62, and C12 with the same three or five coaches.
• All three fireman skill levels anticipate grades and adjust firing sooner.
• We refined wheel and rod appearance and reduced drawing and audio processing overhead at high speed and 4× speed.
• We revised the C62 and C12 operating guides and fixed resource readouts, distance counting, and C12 coupling and uncoupling behavior.

### 1.1.3 — 2026-10-19

• Restored landscape-only display on iPhone, including both iPhone Duo displays. iPad continues to support portrait and landscape.
• Fixed overlapping driving guidance and the coupler close-up in narrow C12 shunting views. Scroll to reach content that does not fit on screen.

### 1.1.2 — 2026-10-17

• Added support for the outer and inner displays of iPhone Duo, with layouts that adapt when the device opens, closes or rotates.
• Fixed detached train weight remaining on the C12 after the coupler lock was lifted. Detached cars no longer add hauling load while the knuckle opens.

### 1.1.1 — 2026-10-11

• Fixed a mismatch between train movement and driving-wheel rotation at low speeds and when stopping on grades.
• Fixed the regulator bar shifting at 100% opening.
• Improved the Joban Line cab layout to keep the current and upcoming gradients and the distance to Toride readable.
• Kept the completed-coupling display visible for about three seconds and improved wheel movement at coupling contact.

### 1.1.0 — 2026-10-09

• Shunting distance now totals all actual locomotive movement in both directions.
• Strengthened light-engine braking, doubled its application and release rates and added Prepare coupler in the cab within 20 m of parked stock.
• Enlarged the coupler plan view and removed the section view. Gentle coupling to stationary stock now produces a short stop depending on weight and approach speed.
• Added 26.34km from Tsuchiura to Toride for C62, with an original gradient diagram, 41 sections and a driving guide based on recorded station positions and gradients. The cab now shows the remaining distance to Toride.
• Light-engine choices now show service mass. Enlarged the Privacy, Help and Extra content links.
• Added the historical JNR shunting speed rule (generally 25 km/h, 45 km/h for a locomotive alone) and its source to the operating guide.
• The menu now centers on D51 driving conditions. C62 and C12 choices appear after purchasing the optional expansion pack.
• Added a task-specific completion checklist to the yard map, showing met and unmet conditions, the next required step and any remaining conditions when ending early.
• Completed coupling now applies the brake automatically, with deceleration following the rise in brake-cylinder pressure.
• The C12 yard brake now acts on the whole consist, with brake force based on locomotive and hauled mass. Application and release take 10–50% longer depending on consist length.
• Coupler close-ups now appear over the driving wheels only within 5 m and disappear when coupling completes. Removed the upper position, distance and coupler bars while keeping the wheel display size unchanged. Gauges, controls and wheels keep the original D51 sizes; the space above the wheels shows the target, direction and remaining distance. Control names wrap and resource readouts adapt to the available width. Shunting results omit the run curve.
• Added separate recorded sounds for lifting the lock and completing coupling. Adjusted the C12 exhaust sound.
• Revised the cast coupler head, knuckle and hinge presentation while preserving contact, rotation, locking and withdrawal behavior.
• Added a one-time expansion pack combining C62 driving, C12 driving and C12 yard shunting.
• Added passenger consists for C62 and short consists for C12, with locomotive-specific wheels, cylinders, mass and inventories.
• C12 shunting now couples automatically on physical contact at 2.5 km/h or less, with moving knuckles and locks and a synchronized clank.
• Added varied yard tasks and assembly/stabling of 12 coaches (480 t) or 30 wagons (750 t).
• D51 and C62 passenger coaches share the same representative loaded 40 t per car.
• Kept the brake control on/off while adding gradual application and release driven by brake-cylinder pressure.
• Added braking-strength bars, quieter airflow-based sounds and a familiar sound as release nears completion.
• Cylinder drains now discharge water according to cylinder pressure and the water remaining.
• Wet drains produce a fuller cloud, changing to a thin steam jet as the water clears.
• Sand now leaves the pipe tip towards the wheel with a slight downward curve.
• Added heat loss, condensation and re-evaporation to the steam-chest model.
• Fixed an abrupt change in the cutoff readout near the reverser's center position.
• Added water discharge rate and total drained water to State, and revised the operating guide.
• Placed steam-chest pressure on the left and boiler pressure on the right.
• Reduced redundant display updates and reused fixed wheel geometry and gauge dials.

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## More apps by Masato Furushima

- [AVECT Train Speed Monitor](https://appshunter.io/ios/app/avect-train-speed-monitor/id6792709658)
- [Pushback2D](https://appshunter.io/ios/app/pushback2d/id6796910377)
- [RTO: Rejected Takeoff Sim](https://appshunter.io/ios/app/rto-rejected-takeoff-sim/id6816637400)

All apps by Masato Furushima: https://appshunter.io/developer/6792693256

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-10-29.*