In this study, ultra high‐speed is defined as a maximum operating speed of >250 miles per hour (mph) (402 km/h). Three technologies could potentially meet the operating speed requirement for UHSGT.

High-speed rail (steel wheel)

High-speed rail (HSR) is a major technology advancement, which is based on the same basic principles as the early railways, namely steel wheel on the trains running railroad tracks

• Current maximum speed: 220 mph (354 km/h)
• Maximum design speed: 250 mph (402 km/h)
• Maximum seating capacity: 1,500
• Minimum horizontal curve: 4.7 miles (7.6 km)
• Maximum gradient: 4%

Magnetic levitation (maglev)

The main feature of the maglev technology is that the trains levitate above the guideway using magnetic fields. There is no contact between the vehicle and the guideway.

• Current maximum speed: 270 mph (435 km/h)
• Maximum design speed: 375 mph (604 km/h)
• Maximum seating capacity: 824
• Minimum horizontal curve: 5.7 miles (9.1 km)
• Maximum gradient: 10%

There are two notable types of maglev technology:

1. Electromagnetic suspension (EMS)
2. Electrodynamic suspension (EDS)

Hyperloop

Hyperloop is a proposed passenger and/or freight transportation using magnetic propulsion to carry vehicles through highly evacuated tubes with very high speed. The main goal of the concept is to reduce the air resistance and therefore to enable very high speeds combined with moderate energy consumption.

• Current maximum speed: 200 mph* (322 km/h)
• Maximum design speed: 760 mph (1,223 km/h)
• Maximum seating capacity: 28 per capsule
• Minimum horizontal curve: 3.0 miles (4.8 km)
• Maximum gradient: Not applicable

* Test track speed, which was limited by length of test track. Source: CH2M, 2017, Ultra‐High Speed Ground Transportation Study: Technology Options Technical Memorandum.