Explore Mexico's Ancient Mayan Sites on a New Train Line

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A new project in the works in Mexico will make exploring the country's historical landmarks easier. As Travel + Leisure reports, the proposed Mayan train line will shuttle tourists around the Yucatán Peninsula, making stops at both famous and lesser-known sites in the area, and connect to the state of Chiapas.

The Mexican government first began discussing the new line—a southern extension of the current Mayan train that runs from Cancún to Tulum—in 2012. Plans were put on hold in 2015 due to funding issues, but they re-entered the national conversation when Andrés Manuel López Obrador made a campaign promise to revive the project. Now, the Mexican president-elect is talking about moving forward with construction after he's sworn into office in December.

When the new Mayan train opens, it will run from Cancún to Palenque, an ancient Mayan village in northern Chiapas. Stops will include Chichen Itza, Mexico's most famous Mayan pyramid, as well as lesser-known archaeological sites that don't see as many visitors. By connecting these places to Cancún, one of the country's most popular tourist destinations, the hope is that more vacationers will add these less-trafficked Mayan sites to their itineraries.

Construction, which will cost an estimated $6 billion to $8 billion, is slated to begin early 2019 and wrap up within four years.

[h/t Travel + Leisure]

What Would Happen If a Plane Flew Too High?

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Tom Farrier:

People have done this, and they have died doing it. For example, in October 2004, the crew of Pinnacle Airlines 3701 [PDF]  was taking their aircraft from one airport to another without passengers—a so-called "repositioning" flight.

They were supposed to fly at 33,000 feet, but instead requested and climbed to 41,000 feet, which was the maximum altitude at which the aircraft was supposed to be able to be flown. Both engines failed, the crew couldn't get them restarted, and the aircraft crashed and was destroyed.

The National Transportation Safety Board determined that the probable causes of this accident were: (1) the pilots’ unprofessional behavior, deviation from standard operating procedures, and poor airmanship, which resulted in an in-flight emergency from which they were unable to recover, in part because of the pilots’ inadequate training; (2) the pilots’ failure to prepare for an emergency landing in a timely manner, including communicating with air traffic controllers immediately after the emergency about the loss of both engines and the availability of landing sites; and (3) the pilots’ improper management of the double engine failure checklist, which allowed the engine cores to stop rotating and resulted in the core lock engine condition.

Contributing to this accident were: (1) the core lock engine condition, which prevented at least one engine from being restarted, and (2) the airplane flight manuals that did not communicate to pilots the importance of maintaining a minimum airspeed to keep the engine cores rotating.

Accidents also happen when the "density altitude"—a combination of the temperature and atmospheric pressure at a given location—is too high. At high altitude on a hot day, some types of aircraft simply can't climb. They might get off the ground after attempting a takeoff, but then they can't gain altitude and they crash because they run out of room in front of them or because they try to turn back to the airport and stall the aircraft in doing so. An example of this scenario is described in WPR12LA283.

There's a helicopter version of this problem as well. Helicopter crews calculate the "power available" at a given pressure altitude and temperature, and then compare that to the "power required" under those same conditions. The latter are different for hovering "in ground effect" (IGE, with the benefit of a level surface against which their rotor system can push) and "out of ground effect" (OGE, where the rotor system supports the full weight of the aircraft).

It's kind of unnerving to take off from, say, a helipad on top of a building and go from hovering in ground effect and moving forward to suddenly find yourself in an OGE situation, not having enough power to keep hovering as you slide out over the edge of the roof. This is why helicopter pilots always will establish a positive rate of climb from such environments as quickly as possible—when you get moving forward at around 15 to 20 knots, the movement of air through the rotor system provides some extra ("translational") lift.

It also feels ugly to drop below that translational lift airspeed too high above the surface and abruptly be in a power deficit situation—maybe you have IGE power, but you don't have OGE power. In such cases, you may not have enough power to cushion your landing as you don't so much fly as plummet. (Any Monty Python fans?)

Finally, for some insight into the pure aerodynamics at play when airplanes fly too high, I'd recommend reading the responses to "What happens to aircraft that depart controlled flight at the coffin corner?"

This post originally appeared on Quora. Click here to view.

Baskin-Robbins Russia Debuts Self-Driving Ice Cream Truck

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While technologists tend to tout the potential benefits of self-driving cars for futuristic commuters, the best use of autonomous driving technology may not involve passengers at all. (Apologies to everyone who wants to nap while they drive.) What we really need are self-driving ice cream trucks.

In Russia, that's already a reality. A driverless ice cream truck from Baskin-Robbins Russia and a company called Avrora Robotics just debuted in Moscow, according to The Calvert Journal.

The VendBot, similar to a smart ice cream vending machine on wheels, debuted at Moscow's Hydroaviasalon conference, an event about seaplane technology and science. The small vehicle is currently designed to move around parks, event spaces, and shopping centers, and can maneuver independently, detecting obstacles and stopping for customers along the way. For its debut, it was stocked with six different Baskin-Robbins flavors.


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Based on videos of the VendBot Baskin-Robbins Russia posted to the company's Instagram account, the miniature truck doesn't come equipped with the jingles U.S. ice cream trucks play incessantly. Instead, it beeps to alert potential customers of its presence instead. Once it stops, customers can order their dessert from a keypad on the side of the vehicle similar to ordering from a vending machine.


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Avrora Robotics, based outside of Moscow in Ryazan, Russia, specializes in developing autonomous vehicles for freight transport, industrial farming, and military use. And now, ice cream delivery.

Unfortunately, there's no mention of Baskin-Robbins bringing its driverless ice cream truck to other countries just yet, so we will have to content ourselves with chasing after human-driven ice cream trucks for a while still.

[h/t The Calvert Journal]

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