# Train Simulator: Network SouthEast Class 121 DMU Add\-On Summer DB entity ID: 9f692f6f\-a537\-4b5a\-85aa\-c0267b4b5fe6 Steam App ID: 258646 Arguably the most useful of first generation diesel multiple units \(DMUs\), the Class 121 ‘Bubble Car’ comes to Train Simulator in distinctive Network SouthEast livery\. The unusual single\-car units were manufactured by Pressed Steel Company from 1960 onwards and introduced by British Rail for use mainly on the Western Region and around London on suburban and branch line duties\. Their distinctive exhaust pipes designed to fit around a large four\-digit headcode indicator box made these units fondly regarded by rail fans for their unpretentious appearance and old\-fashioned interior and performance characteristics\. The ‘Bubble Cars’ became familiar for running Network SouthEast services and upon privatisation of British Rail, the fleet was operated by only one passenger company – Silverlink – with several more units in departmental duties with Railtrack\. Today, two Class 121 models remain in revenue generating service with Chiltern Railways, representing the last chance to ride on 1960s slam\-door stock on the main line in the UK and signifying a remarkably long life for these fans’ favourite\. Five motor cars also remain in preservation across heritage railways in the UK\. The Class 121 for Train Simulator recreates the model as it operated for Network SouthEast between London and the western Home Counties in the 1980s\. Features include the prominent exhaust pipes at the motor end, manual gear change and passenger view with a slightly weathered finish\. The locomotive is also Quick Drive compatible, giving you the freedom to drive the Network SouthEast Class 121 on any Quick Drive enabled route for Train Simulator, such as those available through Steam\. Also included are scenarios specifically for the Great Western Main Line route \(available separately and required to play these scenarios\)\. Scenarios Three scenarios for the Great Western Main Line route: Training: Class 121 Simple & Expert Controls Tourist Shuttle No Go for Greenford More scenarios are available on Steam Workshop online and in\-game\. Train Simulator’s Steam Workshop scenarios are free and easy to download, adding many more hours of exciting gameplay\. With scenarios being added daily, why don’t you check it out now\! Key Features Class 121 ‘Bubble Car’ in Network SouthEast livery Exhaust pipes Manual gear change Passenger view Quick Drive compatible Scenarios for the Great Western Main Line route Download size: 157mb ## Game information - Type: dlc - Developer: Dovetail Games - Publisher: Dovetail Games \- Trains - Release date: Jun 5, 2014 - Coming soon: false - Free to play: false - Parent Steam app: 24010 - Genres: Simulation - Categories: Single\-player, Downloadable Content, Steam Achievements, Full controller support, Steam Trading Cards, Steam Workshop, Steam Cloud, Steam Leaderboards, Family Sharing - Platforms: windows - Website: Not collected - Screenshots: https://shared\.akamai\.steamstatic\.com/store\_item\_assets/steam/apps/258646/ss\_425af9a31ce75396f9737a57fa5256576c67074d\.1920x1080\.jpg?t=1737466427, https://shared\.akamai\.steamstatic\.com/store\_item\_assets/steam/apps/258646/ss\_2a5ef4156c8c4272e03dd86f445207b099311567\.1920x1080\.jpg?t=1737466427, https://shared\.akamai\.steamstatic\.com/store\_item\_assets/steam/apps/258646/ss\_c87c004745c4021d2d923bbdb0de931e1ea9413c\.1920x1080\.jpg?t=1737466427, https://shared\.akamai\.steamstatic\.com/store\_item\_assets/steam/apps/258646/ss\_d257bb0a8ae883f6299cb7c8eb3fef456da24e15\.1920x1080\.jpg?t=1737466427, https://shared\.akamai\.steamstatic\.com/store\_item\_assets/steam/apps/258646/ss\_fe8faf10096524a7bc50397e05f6792e8c6ae54c\.1920x1080\.jpg?t=1737466427, https://shared\.akamai\.steamstatic\.com/store\_item\_assets/steam/apps/258646/ss\_499af8e1359160e888b1372233afce8ca4db708a\.1920x1080\.jpg?t=1737466427, https://shared\.akamai\.steamstatic\.com/store\_item\_assets/steam/apps/258646/ss\_bea389fb7c35c16e808d782d796f3001c43b2e41\.1920x1080\.jpg?t=1737466427, https://shared\.akamai\.steamstatic\.com/store\_item\_assets/steam/apps/258646/ss\_ec1b0b5adba233e0b3693d60743677fb9d070e79\.1920x1080\.jpg?t=1737466427 - Price: 599 minor units USD; discount 70% - Price country: US ## Observed metrics - Current players: Not collected - Steam review count: 12 - Steam positive reviews: 10 - Steam negative reviews: 2 - Steam positive percentage: 83.33333333333333% - Summer DB rating: No native votes Review filters: \{"language":"all","review\_type":"all","purchase\_type":"all","filter\_offtopic\_activity":0\} ## Player history [Seven-day chart data as Markdown](/api/v1/entities/9f692f6f-a537-4b5a-85aa-c0267b4b5fe6/player-metrics?days=7&format=markdown) · [JSON](/api/v1/entities/9f692f6f-a537-4b5a-85aa-c0267b4b5fe6/player-metrics?days=7) Chart values are hourly observed maxima. The sampled 24-hour peak and missing intervals carry explicit coverage; history before collection is unknown. ## Sources and freshness - Catalog membership: store\_catalog - Catalog observed: 2026\-09\-28T16:58:32\.455488\+00:00 - Details observed: 2026\-09\-28T22:44:48\.594529\+00:00 - Player count observed: Not collected - Reviews observed: 2026\-09\-28T22:44:50\.624701\+00:00 Full provenance: \{"urls":\{"price":"https://store\.steampowered\.com/app/258646/","catalog":"https://api\.steampowered\.com/IStoreService/GetAppList/v1/","details":"https://store\.steampowered\.com/app/258646/","players":null,"reviews":"https://store\.steampowered\.com/appreviews/258646"\},"price":"2026\-09\-28T22:44:48\.594529\+00:00","source":"steam","catalog":"2026\-09\-28T16:58:32\.455488\+00:00","country":"US","details":"2026\-09\-28T22:44:48\.594529\+00:00","players":null,"reviews":"2026\-09\-28T22:44:50\.624701\+00:00","language":"en","editorial":null,"membership":"store\_catalog","observations":\{"price":"7b1cebbc\-433c\-4d1c\-b556\-9d14e5f1cdea","catalog":"9c5f2a31\-7e37\-4f20\-b290\-96cb0c087a42","details":"56dfcd4a\-f039\-4612\-8320\-6d7b3b0c8989","players":null,"reviews":"65fc199b\-1835\-423c\-b18a\-03c17c258694"\},"reviewFilters":\{"language":"all","review\_type":"all","purchase\_type":"all","filter\_offtopic\_activity":0\}\} Native rating methodology: \{"count":0,"average":null,"entityId":"9f692f6f\-a537\-4b5a\-85aa\-c0267b4b5fe6","revision":0,"observedAt":null,"methodology":"arithmetic\-v1","distribution":\[0,0,0,0,0,0,0,0,0,0\]\} Steam reviews are not Summer DB votes. Missing data is not zero. Player counts are observations, not historical peaks. A supplemental record does not establish that a game was delisted. [Steam store](https://store.steampowered.com/app/258646/) · [JSON](/api/v1/games/9f692f6f-a537-4b5a-85aa-c0267b4b5fe6)