TECHNICAL ARTICLE AS PUBLISHED IN The Journal January 2019 Volume 137 Part 1 If you would like to reproduce this article, please contact: Alison Stansfield MARKETING DIRECTOR Permanent Way Institution [email protected] PLEASE NOTE THE OPINIONS EXPRESSED IN THIS JOURNAL ARE NOT NECESSARILY THOSE OF THE EDITOR OR OF THE INSTITUTION AS A BODY. TECHNICAL Atmospheric AUTHOR: Alan Whiston railways: FPWI A look to the past to drive the future This White Paper provides a technical This has left people wondering if there is This White Paper provides a technical overview of the development of another way? overview of the development of Atmospheric Atmospheric Railways from 1799 to Railways from 1799 to the current day and the current day and looks at both the The word on everyone’s lips when considering looks at both the Hyperloop Style and the Hyperloop Style and the Piston Style of this is simple; Hyperloop. This system was first Piston Style of systems, and, compares systems, and, compares advantages and discussed by Elon Musk, the tech entrepreneur advantages and disadvantages over existing disadvantages over existing High Speed in 2013 as the future of high speed ground High Speed systems. systems. transportation systems. Moving people or freight from A – B at high speed. This is the A TIMELINE OF ATMOSPHERIC INTRODUCTION future, or is it? RAILWAYS Any proposal for the introduction of a new A 21st Century World requires a 21st century MEDHURST - 1799 innovative and futuristic transport system. transportation mode requires a complete analysis that should address among others the The need for a high speed, technologically George Medhurst was a mechanical engineer following questions - . advanced and fuel-efficient transportation see image 1 and inventor, who came up with the idea of system has intensified in recent decades, moving goods through tunnels pneumatically. It may surprise people that an Hyperloop as highways become more clogged with He first proposed to blow a railed vehicle style system (low tech by our standards, but road traffic and pollution levels increase. An through a tube like a large piston. In 1812 he revolutionary at the time) was first proposed alternative solution has been sought which had developed the idea further and discussed by George Medhurst in 1799, whereby goods would bring fast and efficient travel between the possibility of moving passengers in a would be delivered by being blown through cities, cities and airport hubs and inter-region. similar manner. He also looked at a separate cast iron pipes on carriages. He developed High speed railways have been the backbone idea where instead of the whole vehicle being the idea further to include passengers in 1812. in fast intercity travel since the early sixties the piston, a separate piston placed within a He proposed two alternative system; a fully when Japan’s Shinkansen started operation tube would propel the vehicle. He published enclosed carriage within a pipe which we with its own dedicated high speed line. several papers in relation to moving goods will call the “Hyperloop style” and a carriage Upgrades to existing lines have also brought and people using air pressure, and while he connected to a piston that is enclosed in a increases in speed with several lines in the patented designs for the pumps to power these smaller diameter tube between the running UK operating at 201km/h through the use of systems, he never patented the system itself. rails which we will call the “piston style”. electric rolling stock, diesel rolling stock or new Unfortunately his designs were never put into Unfortunately, Medhurst never patented his hybrid trains. Another consideration has been operation. Maglev. However, each of these systems have ideas, though he is considered the father of the their limitations. atmospheric railway. High speed railways require wheel/rail contact and a power supply, namely traction motors for electrically powered trains, diesel engines powering the wheels of a diesel train, or both systems if a hybrid. The result of this is a relatively large mass for each vehicle to provide the propulsion system. For the maglev system, while there is no contact between the train and the guideway, for some systems wheels are required at low speed (less than 100km/h). However, all systems require magnets to provide the separation between train and guideway, which are also heavy. For both systems, power consumption is an issue, either fossil fuels for diesel and hybrid non-electrified running or electrical power generation from power stations using fossil fuel or renewable energy for the electrically powered systems. Image 1 28 TECHNICAL VALLANCE - 1824 SAMUDA AND CLEGG – 1840 E is the roller that opens the flap valve to allow passage of D, F is the roller behind piston that In 1824, John Valance took out a patent and The Samuda brothers were shipbuilders closes the flap valve re-sealing the pipe. See built a short section of 6’ diameter cast iron and engineers, Samuel Clegg was a gas image 3. tube with rails cast inside. The vehicle was engineer. They Invented a vacuum pipe completely enclosed within the tube and bear system in 1838 and developed a small-scale DALKEY ATMOSPHERIC RAILWAY – 1843 skin was used to seal the space between the model in Southwark at their ironworks after vehicle and the tube. Speed was reduced reading about Medhurst’s system in 1835. An extension to the Dublin to Kingstown (now by opening doors at the front and rear of the In 1840 they leased a half mile of unopened Dun Laoghaire) railway was proposed to vehicle, it worked but was never adopted railway in Wormwood Scrubs. It used a 9-inch Dalkey, an additional 2 miles, which needed commercially. diameter pipe with a 16hp steam engine to climb an average gradient of 1 in 115, with pump for the vacuum which drew the train up a ¼ mile stretch of 1 in 57, deemed too steep PINKUS – 1835 a 1 in 115 gradient on a single line at speeds for the steam locomotives of the time. The up to 30mph. The train then returned to the Treasurer of the company had visited London In 1835, Henry Pinkus patented a system start using gravity. The trial continued for 2 and witnessed the Samuda and Clegg system consisting of a 9 sq. ft square section pipe years. In 1841, Joseph Samuda released a and suggested this would be ideal for the with a partial vacuum, later changed to a small paper entitled “A Treatise on the adaption extension. bore full vacuum pipe, which used a rope to of Atmospheric pressure to the purposes seal the slot where the piston connected to the of Locomotion on Railways”, this gave a In 1843 the extension was opened, which vehicle, rollers lifted the rope clear of the pipe detailed breakdown of the critical parts of an consisted of a 15-inch diameter pipe, with a for the piston connection, then rollers behind atmospheric railway and how they would work. single pumping station at Dalkey. Speeds of re-sealed the pipe. This system had problems In 1844, patents were taken out by the Samuda 30mph were obtained up the gradient, with the due to the rope stretching and breaking the brothers. train returning using gravity. By 1844, 35 train seal, which resulted in Henry not being able to movements a day were taking place carrying attract investors. Though it failed, it became A is the piston tube, B is the valve, C is the 4500 passengers a week. The line operated the prototype for later systems which enjoyed beam holding piston and (W) counter weight, D for 10 years and was the first commercially partial success. is the rod connecting the piston to the vehicle, operating atmospheric railway which attracted inspection from a lot of eminent engineers of the time. See image 4. LONDON AND CROYDON RAILWAY (L&CR) – 1844 A new line was required from New Cross to Forest Hill due to three separate railways sharing the same two track railway, but having different stopping patterns causing congestion. As this section was on a gradient of 1 in 100 it was decided that an atmospheric railway would be ideal after the Dalkey railway had been visited. It opened on 1st May 1844, with an additional section from Forest Hill to Croydon opening in January 1846. Through 1846, several problems started to develop; the static pump station crankshafts started to fail, requiring replacement. The leather flaps sealing the system used tallow, made from animal fat, which attracted rats who ate the leather causing loss of vacuum. The flaps were also affected by extremes of weather, due to the system used on the L&CR not having the steel flap covers used on the Dalkey Atmospheric railway which protected the leather flaps from snow, rain and heat. The L&CR merged with the London and Brighton Railway and a decision was made on 4th May 1847 to convert the line back to a steam locomotive powered system. PARIS TO ST. GERMAIN – 1847 The line from Paris to Pecq was started in 1835 and completed in 1837. However, the section from Pecq to St Germain was deemed to be too steep for steam locomotives requiring a gradient of 1 in 28, the minister of transport had heard of the Dalkey Railway and persuaded the Pereire brothers to adopt the atmospheric railway principle to be able to finish the final 1.5km of the line. The extension was opened Image 2: Timeline of atmospheric railways on the 15th April 1847 and utilised a central 29 TECHNICAL Image 3: Design for an atmospheric railway vehicle 1.