Here’s why high speed trains don’t always save that much time

A train zooms through China. Image: Getty.

It’s not often you hear anyone say people had it easier in the old days, but there is one group for whom  perhaps things have got a bit harder: transport pioneers.

In 1731, the first stagecoach from London to Birmingham took two and a half days. A decade later, simple improvements to the poor quality roads meant that journey time had been reduced by 12 hours.

Today, a train from London to Birmingham takes about 1hr20. In a decade, if the construction of High Speed 2 goes to plan, the most expensive and technologically advanced railway project in British history will have reduced that by… 30 minutes. You can’t help feeling a bit short-changed.

Italy last week rejected a plan to increase the speed of its high-speed Milan to Rome line from 300kmph (185 mph) to 350kmph (220 mph). This would have been a fairly big speed increase – but the trains would only reach Rome 10 minutes earlier, and the transport ministry decided it simply wasn’t worth the cost of the extra power needed and the damage to the tracks caused by faster trains.

This all comes down to a cruel twist of mathematics: a small improvement to a slow mode of transport saves far more time than a much bigger improvement to fast one. If you double your speed then, ignoring complications like acceleration and corners, you halve the journey length. But each doubling requires a bigger increase in speed, while each halving results in less time being shaved off.

Here’s a quick example. Let’s say you want to go 640 miles – that’s roughly the straight-line distance from Paris to Vienna, or from London to Edinburgh and back. How long will that take you?


On foot, your average walking speed without roads would probably be about 2-3 mph. Let’s assume 2 mph for now. Walking those 640 miles would take you 320 hours, or about 13 days (not taking into account time to sleep or rest).

With a fit horse, your walking speed could be a sustained 4 mph. That tiny 2mph increase doubled your speed, and halved your travel time, cutting the journey by an incredible 160 hours – almost a week.

With a few more horses, good roads and some regular coaching inns, a stagecoach could do 8 mph. That lets you cut another 80 hours off the journey.

Once railway technology arrives, we can double the speed again to 16 mph – roughly the limit on early lines like Stockton-Darlington or Manchester-Liverpool. At this speed, your journey takes 40 hours. The savings aren’t as great as they were before, but cutting nearly 2 days off the journey isn’t bad.

Double the speed to 32 mph, the journey now takes 20 hours. Double again to 64 mph, it takes 10. At 128 mph – just about the highest speed possible on the British train network outside High Speed 1 – those 640 miles can be covered in just 5 hours.

But now things start getting difficult.

To double the speed again means increasing by another 128 mph, to 256 mph. No regular train runs at this speed anywhere in the world, but there is one contender: the Shanghai maglev. This can reach speeds of 270 mph but at a huge cost. The line is incredibly expensive, and makes a loss every year. If you travelled those 640 miles at 256 mph, the journey would take around 2.5 hours. For all that effort, you’ve saved 150 minutes. It might still be worth it – but it’s a lot of investment for a small gain.

Finally, we can double it one more time to 512 mph. This is roughly the cruising speed of an Airbus A320. Flying all the way, those 640 miles are covered in 75 minutes. The time savings are getting very limited now.

Speed (in miles per hour) and time taken (in hours) to cover 640 miles. The introduction of the horse was probably more important than maglev. Sorry.

Take into account the time needed to accelerate up to top speed and stop at stations along the way, and all this explains why the benefits of exciting high-speed rail projects can be underwhelming. Most intercity transport in the western world is already quite fast: eking out a few more miles per hour makes little difference to journey times except on the longest journeys.

This doesn’t mean there’s never a case for high-speed rail – its convenience can attract air passengers, and the (relative) glamour of express trains can attract passengers who wouldn’t otherwise use railways. But saving time is not necessarily a major advantage.

There is an exception: very long journeys. Over thousands of miles those small time savings can still add up. France and Germany have highly successful intercity high speed lines, because their routes stretch right across the country and beyond into neighbouring countries. If the government ever extends High Speed 2 into Scotland, or manages to integrate cities like Manchester into the Eurostar network, rail passengers might get to enjoy some really good time savings.

For an extreme example, see China, where the 1,400 mile long Beijing-Guangzhou high-speed line more than halved journey times between the two cities. Given that the slower train took over 21 hours, shaving 13 hours off meant it was well worth it (even if many people prefer to fly). Just don’t expect anything quite so dramatic on our little island.

 
 
 
 

Mexico City’s new airport is an environmental disaster. But it could become a huge national park

Mexico City’s new Norman Foster-designed airport, seen here in a computer rendering, is visually striking but environmentally problematic. Image: Presidencia de la República Mexicana/creative commons.

Mexico City long ago outgrew the two-terminal Benito Juárez International Airport, which is notorious for delays, overcrowding and canceled flights. Construction is now underway on a striking new international airport east of this metropolis of 20m. When it opens in late 2020, the LEED-certified new airport – whose terminal building was designed by renowned British architect Norman Foster in collaboration with the well-known Mexican architect Fernando Romero – is expected to eventually serve 125m passengers. That’s more than Chicago O'Hare and Los Angeles’ LAX.

But after three years of construction and $1.3bn, costs are ballooning and corruption allegations have dogged both the funding and contracting process.

Environmentalists are also concerned. The new airport is located on a semi-dry lake bed that provides water for Mexico City and prevents flooding. It also hosts migrating flocks and is home to rare native species like the Mexican duck and Kentish plover.

According to the federal government’s environmental impact assessment, 12 threatened species and 1 endangered species live in the area.

The airport project is now so divisive that Andrés Manuel López Obrador, the populist winner of the country’s 2018 presidential campaign, has suggested scrapping it entirely.

An environmental disaster

Mexico’s new airport sits in a federal reserve. Image: Yavidaxiu/The Conversation.

I’m an expert in landscape architecture who studies the ecological adaption of urban environments. I think there’s a way to save Mexico’s new airport and make it better in the process: create a nature reserve around it.

Five hundred years ago, lakes covered roughly 20 percent of the Valle de Mexico, a 3,500-square-mile valley in the country’s south-central region. Slowly, over centuries, local residents – first the Aztecs, then the Spanish colonisers and then the Mexican government – built cities, irrigation systems and plumbing systems that sucked the region dry.

By the mid-20th century, the lakes had been almost entirely drained. In 1971, President Luís Echeverría decreed the area a federal reserve, citing the region’s critical ecological role for Mexico City. The smattering of small lakes and reforested land there now catch and store runoff rainwater and prevent dust storms.

The new airport will occupy 17 square miles of the 46-square-mile former Lake Texcoco. To ensure effective water management for Mexico City, the airport master plan proposes creating new permanent water bodies to offset the lakes lost to the airport and cleaning up and restoring nine rivers east of the airport. It also proposes planting some 250,000 trees.

The government’s environmental assessment determined that the impacts of the new airport, while significant, are acceptable because Lake Texcoco is already “an altered ecosystem that lost the majority of its original environmental importance due to desiccation and urban expansion.” Today, the report continues, “it is now only a desolate and abandoned area.”

Environmentalists loudly disagree.

Make Mexico’s airport great again

I see this environmental controversy as an opportunity to give Mexico City something way more transformative than a shiny new airport.

Nobody can entirely turn back the clock on Lake Texcoco. But the 27 square miles of lake bed not occupied by the airport could be regenerated, its original habitat partially revitalised and environmental functions recovered in a process known as restoration ecology.

I envision a huge natural park consisting of sports fields, forests, green glades and a diverse array of water bodies – both permanent and seasonal – punctuated by bike paths, walking trails and access roads.

The airport will come equipped with new ground transportation to Mexico City, making the park easily accessible to residents. Extensions from the surrounding neighborhood streets and highways could connect people in poor neighbourhoods abutting the airport – dense concrete jungles like Ecatepec, Ciudad Nezahualcoyotl and Chimalhuacan – to green space for the first time.

The nine rivers that empty into Lake Texcoco from the east could be turned into greenways to connect people from further out in Mexico State to what would become the area’s largest public park.

Space could also be reserved for cultural attractions such as museums, open and accessible to passengers in transit.


New master plan

This idea is not as crazy as it sounds.

As early as 1998, Mexican architects Alberto Kalach and the late Teodoro González de León proposed rehabilitating the lakes of the Valley of Mexico. Their book, “The City and its Lakes,” even envisaged a revenue-generating island airport as part of this environmentally revitalized Lake Texcoco.

Under President Felipe Calderon, Mexico’s National Water Commission also proposed building an ecological park in Lake Texcoco, which was to include an island museum and restore long-degraded nearby agricultural land. But the project never gained traction.

Granted, turning a large, half-constructed airport into a national park would require an ambitious new master plan and a budget reallocation.

But in my opinion, evolution and change should be part of ambitious public designs. And this one is already expected to cost an additional $7.7bn to complete anyway.

Toronto’s Downsview Park – a 291-acre former air force base turned green space – has transformed so much since its conception in 1995 that its declared mission is now to “constantly develop, change and mature to reflect the surrounding community with each generation.”

Local communities neighboring Mexico City’s new airport were not adequately consulted about their needs, environmental concerns and their current stakes in the Lake Texcoco area. A revamped park plan could be truly inclusive, designed to provide recreation and urban infrastructure – and maybe even permanent jobs – for these underserved populations.

Presidential race

Three of the four candidates in Mexico’s July 1 presidential election wanted to finish Mexico City’s new international airport. But eventual winner López Obrador was not so sure.

Early in his campaign, he said he would cancel it if elected. Instead, López Obrador suggested, a former air force base could become the new international terminal. It would be connected to Benito Juárez airport, 22 miles south, by train.

López Obrador has since said he would support completing construction of the new international airport if the remaining financing came from the private sector, not the Mexican government. Currently, some two-thirds of the project is funded by future airport taxes.

The ConversationLópez Obrador’s promise to review and likely upend the airport plan could open the door to its wholesale transformation, putting people and nature are at the core of a plan ostensibly designed for the public good.

Gabriel Diaz Montemayor, Assistant Professor of Landscape Architecture, University of Texas at Austin

This article was originally published on The Conversation. Read the original article.