BUDAPEST METRO LINE 4 FEASIBILITY STUDY

Oktober 1996

SECTION C - ENGINEERING ISSUES

ANNEX C

Section C reports the key engineering issues to be addressed to implement a metro line. Rolling Stock design, infrastructure aspects and required equipment to operate Metro line 4 are successively examined. Operation principles are summarised. This section ends with the overall capital cost estimation, in accordance with assumptions of staging alternatives.

Rolling Stock design

Introduction

This chapter describes the general characteristics and performances of the rolling stock designed on the basis of the refined passenger forecasts (refer Section B). The objective of the Second Stage was to optimise the rolling stock, so as to optimise in particular the station design, while considering the appropriate level of service and level of comfort to provide to the passengers.

General characteristics

Rolling Stock Diagram

Only two types of vehicles are proposed to be included within the train consist, so as to optimise the overall train cost, as follows :

• Vehicle without cab

• Vehicle with cab

Train Consists

A cab in the trailer allows in particular to design a train consisting of only 2 different types of vehicles, which is more economical than a train consisting of 3 or more different type of cars.

A three-phase asynchronous propulsion should allow a slight increase of power at the axle. A power of 200 kW per axle complies with the requirements of a reduced clearance of the rolling stock.

Under these conditions, two types of train consists can be designed to comply with the operation requirements and the passenger forecasts: one consisting of 4 cars, the other comprising 5 cars.

The 4 Car train set includes 2 traction units and 2 hauled vehicles is recommended. It is more cost effective and provides a good level of service.

The 5 car train set should include 2 trailers equipped with a driver's cab and 3 motor coaches.

• Train capacity

Considering the two train consists, the related capacity is as follows :

	Seated	Standing		Total Capacity
Capacity	Peak Hours /(Off-peak Hour)	4/m2	5/m2	4/m2	5/m2
Vehicle without Cab	32 / (56)	104	130	136	162
Vehicle with Cab	28 / (52)	103	129	131	157
4 car Train Set	120 / (216)	414	518	524	638
5 car Train Set	152 / (272)	518	648	670	800

Main dimensions

	Dimensions
Vehicle without cab
Length at body ends	15.200 m
Length over buffers	15.500 m
Width	2.600 m
Height	3.500 m / 3.600 m
Height of floor	1.040 / 1.050 m
Vehicle with cab
Length at body ends	15.800 m
Length over buffers	16.250 m
Width	2.600  m
Height	3.500 m / 3.600 m
Height of floor	1.040 / 1.050 m
4 Car train set
Length at body ends	63.060 m
Length over buffers	63.500 m
5 Car train set
Length at body ends	78.560 m
Length over buffers	79.000 m

It should be noticed the 79 m outer length of a 5 Car train set, that will support the station design. Station platform will be designed on a standard 80 m length.

Rolling stock performances

Operating Capacity

• Peak hour

Based on a 2 mn train headway, the total capacity supplied is between 20,100 and 24,000 passengers per hour, per direction, (depending on the 4 or 5 standees per m² level of comfort, under the most comfortable conditions: 152 seated passengers per train, to compare to the expected maximal passenger flow forecasts (Section B). If further needed, a higher level of service corresponding to 90s train headway could be supplied, the capacity being between 26,800 and 32,000 passengers, the technical equipment, especially power supply being dimensioned on that assumption (refer to Chapter C-3).

	Total Capacity 2 mn headway		Total Capacity 90s headway
Capacity	4/m2	5/m2	5/m2	5/m2
5 car Train Set	20100	24000	26800	32000

• Off-peak hour

During off-peak hours, each train capacity being 272 seats, the capacity supplied is 8,160 seated passengers, for a 2 mn train headway.

Station dwell time - Duration of emergency evacuation

The 3-side-door diagram theoretically allows for each door enough space for 3 persons in line. It is generally assumed that the boarding time or getting off time for each passenger is around 0,6 s. Under these conditions, each vehicle boarding/alighting capacity is 5.4 pax/s.

• Station dwell time

Theoretical station dwell time is generally calculated considering one third of the passengers getting off from the most loaded vehicle (vehicle without cab), and the same amount of passengers boarding. Theoretical estimation gives around 20 s for a 4 pax/m² train set and 25 for a 5 pax/m² train set.

To calculate the commercial speed on the line, the most unfavourable time is considered.

• Duration of emergency evacuation

The theoretical duration of emergency evacuation is calculated according to the same criteria of passengers capacity for the most loaded vehicle. It is given to be around 26 s for a 4 pax/m² train set, 30s for a 5 pax/m² train set.

Maximum grade of the right of way

• Evaluation of vehicle total weight

Unladen weight

It is assumed that the trailers with driver's cab are equipped with a compressor unit, a secondary battery and a DC/AC converter for the supply of control circuits and power for auxiliaries (light, heating/ventilation, battery charger, etc.). The motor coaches do not include any auxiliary group.

Weight of a Tc trailer: Mt_vom = 22,000 kg,

Weight of an M motor coach: Mm_vom = 28,000 kg.

The weight of a 5 car train set ready for service is as follows:

M_vom: 128,000 kg.

Rotational weight

Rotational weight is evaluated to:

M = 6,000 kg for motor coaches,

T = 1,500 kg for trailers.

• Passenger load and Total weight of a train

Standard passenger's weight generally considered is 70 kg.

	4 pax/m²	5 pax/m²	8 pax/m²
Passenger load	Q4 = 46 900 kg	Q5 = 56 000 kg	Q8 = 72 100 kg
Total weight	M4 = 174 900 kg	M5 = 184 000 kg	M8 = 200 100 kg

Maximum grade calculation

In preliminary evaluations, the traction efforts are assumed proportional to the vehicle load, the acceleration remaining constant regardless of the train load. The efforts at the wheel are due mainly to the traction motor power and to the wheel-rail available friction at the time of the excitation, refer to Figure C-5 below.

• Single contingency

The maximum effort at the wheel, unladen mass, is:

Mm_vom × g × adh:

• Fjmax = 3 × 28,000 × 9.81 × 0.21 = 173,000 N

The effort at the wheel with one traction power equipment damaged is:

Fjmax × 2/3 = 115,300 N

It is assumed that, starting is possible when the acceleration is equal or greater than 0.1 m/s². The general formula of the efforts in grade is:

(M_vom + M) × 0,1 + (M_vom × g × sin) Fj

i.e.:

sin (Fj - (M_vom + M) × 0.1) / M_vom × g

sin 0.08,

which means that a 80‰ gradient is theoretically feasible.

A damage on one traction power equipment is not the determining factor for the magnitude of the maximum grade on the system.

• Common mode contingency

It corresponds to a damage immobilising a whole train. In that case, after unloading of its passengers, the following train pushes the damaged train. An empty train gives "help" to a train loaded at 5 pax/m², for example.

The maximum gradient is:

sin 0.045,

which means that a 45‰ gradient is theoretically feasible under these extreme conditions. Indeed, the maximum grade level in line should not exceed 40‰.

For the 4 car train set, this type of contingency practically corresponds to a damage on motor coach equipment. The maximum grade should not exceed 40‰. In very exceptional cases, the gradient might reach 45‰.

• Single contingency on a loaded train (5 pax/m²)

The maximum grade is:

sin 0.053,

for an excitation to which has been applied the friction coefficient.

It is assumed that a loaded train, suffering a single contingency, would be able, in very exceptional cases, to pass a 50‰ gradient.

Static load per Axle

Under a load of 8 pax/m², the static load per axle is:

11.2 t.

Under a load of 10 pax/m², the static load per axle is:

12.1 t.

Operating and commercial speeds

Based on standard design speed and depending on the vertical and horizontal profiles, the operating speed can reach 80 kph.

According to the alignment station spacing and the operation contingencies, the commercial speed is given to 28 kph.