Double Decker Sleeper Coach

Abstract

The passenger carrying capacity in AC Chair Cars has been increased by adopting the Double Decker (DD) concept. The concept considered in the use of space between bogies and effectively created three levels – LD (Lower Deck), UD (Upper Deck) and MD (Middle Deck) – for passenger accommodation. This article examined the possibility of enhancing the level of service in sleeping accommodation by considering the provision of only lower berths in a coach to eliminate the inconvenience of using an upper berth and its impact on the capacity.

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Introduction

Indian Railways (IR) operates trains on its long distance passenger services with sitting and sleeping accommodation in Air Conditioned (AC) and non-AC coaches.  The accommodation – sitting and sleeping – is offered at different Levels of Service (LOS) across the two categories of coaches.

The seating accommodation is 3+3 transverse arrangement in non-AC and 2+2 (Executive) and 3+2 (Economy) arrangements in AC Chair Cars (CC). The overall seating capacity in Executive (56) AC-CCs is almost half of that in Non-AC-CCs (100) and three-fourths in Economy (78) AC-CCs. The capacity is different among coaches with different dimensions.

Sleeping accommodation in two Classes – First and Second - is provided in trains either in 2-Tier [2T - with a Lower Berth (LB) and an Upper Berth (UB)] or 3-Tier [3T - including a Middle Berth (MB)] format. The accommodation in First Class always has a 2T format. The accommodation in Second Class is either in 2T or 3T format with trains usually having more 3T coaches than 2T coaches to cater to the larger transport demand. The berth arrangement in 3T coaches is in 3T format for berths provided in the transverse direction and in 2T format for those provided in the longitudinal (commonly – Side Berths) direction. IR commonly uses coaching stock of two makes – ICF and LHB – with each having different passenger carrying capacities  in AC First Class (AC-1) and AC Second Class (AC-2T / AC-3T).

Capacity Enhancement

Sleeping Accommodation – IR is making continuous efforts to enhance the capacity for passenger services through increasing the passenger carrying capacity of coaches in addition to improvements in other aspects of railway operations such as signaling and augmentation (additional tracks) of current network and; developing high speed freight and passenger networks. Capacity of AC-3T coaches was enhanced by changing the format of side berths from 2T to 3T by providing a MB. This increased the capacity of the coaches by 8 to 9 berths depending on the coach dimensions and make. This enhancement was however withdrawn as the LOS was not acceptable to the passengers. The rising economy and the desire of better LOS by passengers was the reason for such non acceptance.

Sitting Accommodation – IR in its efforts to increase the sitting passenger carrying capacity in AC-CCs has adopted the Double Decker (DD) concept and developed the same with Economy Class capacity ranging between 120 (Layout shown in figure – Source Maintenance Manual LHB Coaches - Pg 10) and 136 passengers (Pg 8). DD-AC-CCs with Executive Class accommodation have a capacity for 68 passengers.

LOS – Sleeping Accommodation

LOS in general is improving over the period across different facilities.  For example, the number of AC coaches in a train consist are increasing and non-AC coaches are decreasing. The level of LOS for sleeping berths can be assessed considering the width and vertical placement (LB, MB and UB) of berths. Considering the vertical placement of berths both AC-1 and AC-2T have similar measure of LOS for there being only two levels (LB & UB) of berths in these coaches. The LOS in AC-3T in comparison is lower with the inclusion of MB. Considering the berth length and aisle width both AC-2T and AC-3T has similar LOS. The width of berths in AC-1, AC-2T and AC-3T are decreasing in the order and also of the leg room between berths in a cabin indicating decreasing LOS across different classes of coaches. Considering the number of lower berths in a coach the LOS of both AC-2T and AC-3T is similar.

LOS and Capacity Enhancement – Sleeping Accommodation

The capacity of sitting accommodation was enhanced by the use of the DD concept in the design of a coach by marginally increasing the height of the coach and use of well space between the bogies. Although it is termed a DD, in practice the space for passenger use is available in three decks. The upper and lower decks of DD Coach use the vertical space between bogies. The space above the bogies which is at the platform level can also be used for passenger services and is termed middle deck or mezzanine deck. The space thus generated in the three decks was considered for providing only lower berths for sleeping accommodation and the concept layout prepared as shown. The concept considered placement of three parallel rows (one in the middle and two on sides) of berths in the longitudinal direction. The conventional coach considers parallel berths in the transverse direction and a sequence of longitudinal berths on one side of a coach. The arrangement indicates that the dimension of berths, on both sides, in lower and upper decks could be 1950 x 630 mm. The dimension of berths in the middle row could be 1950 x 620 mm. This arrangement provides 14 berths in the lower deck and similar number could be arranged in the upper deck giving a total of 28 berths in the two decks together. These are 4 more than the maximum number of total berths in AC-1 class and 16 more than the maximum number of lower berths in the coaches of the same class. This suggests enhancement of LOS (being only lower berths) and capacity simultaneously. The absence of MB and UB eliminates the inconvenience and difficulties associated in accessing the same and thus improving the LOS. The capacity can be further increased by provision of berths with slightly lower LOS through berths of the same width (630 mm) but reduced / constrained length (4 berths of 1792 mm and 2 berths of 1888 mm) in the middle deck. Therefore the total capacity of the coach in a single level sleeper berth format is 34.  Thus the overall capacity in DD Sleeper Coach is more than 40 percent of the maximum capacity available in two levels in an AC-1 class coach. Of course the width of berths in DD Sleeper Coach is constrained in comparison to that in AC-1 coaches currently in operation. This however, is wider than the width of 530 mm of flatbed seats available in some airlines.

The width of berths on the two sides of the coach can be increased to 740 mm to enhance the LOS but would require deletion of berths in the middle row on both upper and lower decks resulting in reducing the overall capacity to 26. Even in this case the overall capacity is higher than the maximum capacity available in the conventional AC-1 class coaches.

These two options can be designated to represent First (later option) and Second (earlier option) class versions of DD and labeled DD-1L and DD-2L with “L” indicating the provision of only LBs in the coach. The height of the decks appears sufficient (Slide 59) to consider provision of berths in 2T format. If this is achieved the capacity of the two versions can be doubled. The DD coaches with a 2T format of berths can be labeled DD-1U and DD-2U respectively to suggest the provision of a UB also in the coach. The provision of berths in a 2T format enhances the capacity at a better LOS, by the elimination of a MB, to similar levels as that of operating AC-2T and AC-3T coaches.

DD Sleeper Services

Passenger services using DD Sleeper Coaches (DD-SC) can be considered for medium distance journeys between cities which can be covered overnight. Passengers moving such distances using ABC (Air/Bus/Car) modes can be attracted to travel DD-SCs for reasons of better LOS in comparison to that in existing coaches. Some of the ABC mode travelers could be those who are lost (cancelled journeys) to rail for having not obtained accommodation in a LB and are reluctant to travel by either MB or UB.  DD-SCs with a 1+1 or 1+1+1 berth arrangement could be an attraction to some of the bus passengers including those of even in sleeper buses in which it is either 2+2 arrangement of near flat facility (reclining) seats or 2+1 and 1+1 flat berth arrangement in 2T format. Car and air travelers could get attracted to DD-SCs, due to better LOS, to avoid hassles associated with starting early and/or taking early morning flights to reach their destinations. This suggestion does not preclude consideration of DD-SC services on longer routes.