---
title: "Britain Was Still Trying to Make Steam Trucks Happen in the 1930s"
description: "Sentinels could chugga-chug-chug their way up to 60 mph, but speed wasn't enough to overcome the inconvenience of steam power."
date: "2021-04-26"
modified: "2021-04-26"
authors:
  - name: "James Gilboy"
    job_title: "Contributing Writer"
    link: "https://www.thedrive.com/authors/james-gilboy"
url: "https://www.thedrive.com/news/40298/the-sentinel-s-type-steam-wagon-was-the-external-combustion-engines-last-stand"
categories:
  - "Culture"
  - "History"
  - "News"
---

# Britain Was Still Trying to Make Steam Trucks Happen in the 1930s

![](<https://www.thedrive.com/wp-content/uploads/images-by-url-td/content/2021/04/Sentinel_S4_steam_waggon_Holmevalian.jpg>)
*\<em\>www.thedrive.com</em>*

Before internal combustion engines won over the automotive industry, they had to fight off rival forms of propulsion like [early electric drive tech](<https://www.thedrive.com/news/37216/forget-the-hummer-ev-gmc-made-an-electric-truck-in-1913-called-the-model-3>), and even grandfathered-in steam engines. This mature but soon-to-be-obsolete legacy technology didn't go down without a fight, though, and in the 1930s it reached its pinnacle in steam wagons like the Sentinel S type.

The S type was the last new steam truck introduced by one of steam's few remaining stalwarts, the highly regarded Sentinel Steam Waggon Works. Hitting the streets in 1934, the S type (short for *Standard*) was a cab-over style truck fueled from within the cab, done by scooping coal down a chute to a high-pressure boiler.

![message-editor%2F1619196463706-sentinel\_steam\_lorry\_15450985806.jpg](<https://www.thedrive.com/wp-content/uploads/content-b/message-editor/1619196463706-sentinel_steam_lorry_15450985806.jpg>)
*Sentinel S6 six-wheeled steam truck, *CC0 1.0 Universal (CC0 1.0) Public Domain**

This boiler pressurized steam to as high as 250 psi—up there with [some of the most powerful steam locomotives ever built](<https://www.thedrive.com/news/36692/the-top-10-coolest-trains-of-all-time>)—before venting it into a four-cylinder engine; a single-acting design with steam pressure on only one side of the piston. Power traveled out through a two-speed transmission to worm gear-driven axles, as many as four of which were available on the eight-wheeled S8. Far more common, though, were the six-wheeled S6 and four-wheeled S4, which apparently comprised all but nine of the S type's [reported](<https://www.sentineldriversclub.com/history_1941-2017.html>) 3,750-unit production run.

https://youtube.com/embed/nj6HbWw4wSM

Despite the S type's ability to reportedly [maintain speeds of 45 mph](<https://www.gtm.org.uk/exhibitions/gtm-permanent-collection/sentinel-steam-waggon/>) and top out at 60, the writing was on the wall for this steam wagon, which [Sentinel itself admitted](<https://www.sentinelmanufacturing.co.uk/our-history>) was both more inconvenient to operate *and* less capable than [any comparable diesel](<https://www.thedrive.com/news/33363/cummins-swapped-1949-dodge-power-wagon-restomod-merges-old-glory-with-new-tech>). By the late '30s, the S type had more or less been phased out in favor of in-house diesels, with Sentinel itself switching over to wartime manufacture before the decade's end.

![message-editor%2F1619196612272-sentinel\_s-6\_steam\_truck\_ca\_1956.jpg](<https://www.thedrive.com/wp-content/uploads/content-b/message-editor/1619196612272-sentinel_s-6_steam_truck_ca_1956.jpg>)
*Sentinel S6 operating in Argentina, 1949, *Public Domain**

The Sentinel S6 apparently enjoyed one final hurrah, with an Argentinean coal mine ordering a fleet of 100 units some time between [1949](<https://www.gracesguide.co.uk/Sentinel>) and 1956, though this was but a flash in the pan for the waning Sentinel. By 1956, Sentinel ceased truck production entirely, and in short order, much of the company was absorbed by Rolls-Royce. Though this marked the end of the line for Sentinel as a producer of vehicles, the company today lives on as a small independent manufacturing firm, one that no doubt does good business in boiler parts.

https://youtube.com/embed/skG-YYGwoFI

*Got a tip or question for the author? You can reach them here: james@thedrive.com*

## Author
James is a former staff writer for The Drive. He has changed the conversation around electrification, debunked misinformation online, and become a prominent hunter of what he calls "automotive cryptids."

### Author social links  
[Instagram](<https://instagram.com/jamesgilboy>)