*Comparison

 

 

Table 1. Comparison with other systems.

 

Subway

PRT

BT

Remark

Capacity (persons/h)

20~40 K

2~10 K

18~360 K

Highest Capacity

Moving speed (km/h)

31~39

20~40

90~105

Swiftest moving

Vehicle price ($)

800~1500 K

20~250 K

5~20 K

Cheapest price

Stopping method

On-line

Off-line

Branch-line

Best structure

 

Table 2. Expected line capacity and alighting capacity of the BT system.

LINE CAPACITY

Effective traffic volume (vehicles/h)

TERMINAL CAPACITY

Embarking/disembarking capacity (vehicles/h)

Headway
(s)

Capacity/ lane/h (vehicles/h)

Number of the mainline lanes

Berth arrangement type

Number of berths

2

4

6

10

4

6

8

12

0.5

7200

7200

14400

21600

36000

Reversible

360

540

720

1080

1.0

3600

3600

7200

10800

18000

Multi-series

1200

1800

2400

3600

If 10-seater cars are used, the capacity is 36,000~360,000 persons/h.

Table 3. Comparison of the characteristics.

Classification

Comparative Item

SUBWAY       (in Seoul)

BT (estimated)

Remarks

Cost

Weight of train/vehicle

300~430 ton

1 ton

Reduced by a factor of 300

Construction cost per km (whole costs)

$60 million

$8 million

BT: two-lane elevated.        Subway in USA was $ 40~105 million.

Fare

$0.5

$0.5

For a distant of 10 km

20km construction period

60 months

12 months

BT: two elevated lanes

Mobility

Carrying capacity (ppdph)

40,000~63,000

360,000

BT: maximum of five lanes per direction

Travel speed per hour

35 km

102 km

Subway: 31.2~35.9km/h

Peak hourly volume (Throughout the whole of Seoul)

420,000 persons

1,800,000 persons

Subway: 7 lines (218km)                 BT: 600km (total length)

Accessibility

Number of stations/terminals

197 each

800 each

Four times including various and direct

Distance between stations

1,100 m

500 m

Point at which traffic occurs.

 PRT Analysis
The carrying capacity of PRT is too small.
If a PRT
is operated using eight stations with three berths, then 1400 vehicles per hour can be managed. (350 vehicles per hour per station times four)
If each vehicles has three passengers, then the capacity is 1,400×3= 4,200 passengers per hour.
If there are 1.4 passengers per vehicle, then the capacity is 1,400×1.4= 1,960 passengers per hour.
Therefore, such a system carries less than
2,000 passengers per hour.

The headway must be below 2.5 seconds.
The vehicles rate must be over 40 vehicles per km (1000 m/(2.5 s × 10 m/s))

A capacity of 2,000 passengers per hour can be achieved using a system that has

* Eight stations having 24 berths (8 x 3 = 24),

* a headway time of under 2.5 s,

* a vehicle density of over 40 vehicles per km, and

* a well coordinated operating system.

 

 

 BT Analysis
A high-speed operation of the BT system will be ensured by,

1. A high degree of straightness from installation along the center of wide roads.

2. High-speed passing on the connecting ramps of interchanges is possible owing to the large turning radius of the interchange.

3. Ample acceleration when entering the main line from a branch line, and deceleration when turning onto a branch line.

4. Traveling conditions are similar to those of an expressway.

 

A high-frequency service from the BT system can be guaranteed because,

1. It is a structure in which many vehicles can enter the main lines in a continuous manner from multiple terminals that contain many berths in a row.

2. The interchange structure enables high-speed operation and maintains vehicles at regular intervals on the main lines by employing large radius ramps.

3. The terminal structures have ample alighting capacity for multiple vehicles entering from main lines that provide a high-frequency service.

 

Factors determining a high capacity.

1. High speed running.

2. High frequency service.

3. Multi-lanes.

4. Terminals have structures that enable a high alighting/entering capacity.