Draft Safety Case The Kitson Tunnel and Dell Deviation


Below is the text of the draft Safety Case for The Kitson Tunnel and Dell Deviation. It has been looked at today by key players and I have amended it following their comments. It will be going to the committee next Wednesday so I thought it would be worth while sharing it more widely before in case any one else would like to comment.

The formatting is lost when adding to the blog so ignore how it looks

Introduction

This document provides the Safety Case, including risk assessment, for The Kitson Tunnel 2017 and Dell Deviation (KT&DD) at Ravensprings Park. This document is base on the Health and Safety Executive’s guidance note Passenger Carrying Miniature Railways – Guidance on safe practices[1] (PCMR). It should be read in conjunction with BHME’s Standard Operating Procedures, as amended by this document. It uses a risk-assessed approach to provide a safe environment for the operation of the KT&DD.

Conclusions

The tunnel and deviation as described offers a greatly improved safety for the operation of passenger carrying miniature trains that meets all the functional requirements of PCMR due to removel of the shared tunnel and adoption of fully automatic signals throughout this section.

Scope

This document covers the extent of KT&DD starting at the Covered Station level crossing continuing of a slightly new alignment following the West boundary before entering the Kitson Tunnel (KT) which curves under the main entrance to Ravensprings Park and under the toilet block, it enters the Dell hugging the Northern boundary before turning to enter the existing Loop/Mail line Point AP1. In addition it covers, the alterations made to the entrance area and car park between the ground level track and the raised track, the L&Y Shed Siding and Operating Procedures Ground Level Track (Revised 1 April 2017).

Tunnel and Deviation Description

Background

The KT&DD project stems from the issues in the continued use of the ‘Shared Tunnel’ (ST). The ST was one of the earliest built at Ravensprings, it is less than 6’ tall and is too narrow for two train operation despite having both the ground level and raised level tracks running through it. As a consequence the two different tracks had to have an interlinked signalling system to ensure only one train was in the ST section. This limited both track capacities on open days contributing to queues on both track, with additional problems for raised track trains restarting from a dead stop on the Ramps Curve.

Route

To avoid the ST the only available route was to the outside of the ST and down the Dell. Due to the shape of the site and minimum radius required it was impossible not to go under the Toilet Block.

The initial plan was to turn left after the L&Y Tunnel (L&YT) and then turn right to go under the toilets; however, due to need to reinforce the foundations of the toilets it was found that the descent was too steep for safe operations. This led to the decision to provide a new alignment from the Level Crossing near the West Boundary and to the entrance side of the L&YT curving under the main entrance area. This brought the added benefit of removing 14” from the climb and allowing a level track through the KT.

The final design for the KT includes a 24 m ‘cut and cover’ tunnel which curves under the main entrance, 2.5m tunneled section under the toilet block and a 4m portal extension into the Dell. Advice received from our architects placed restrictions on the width of both sections of the tunnel: -

  1. Bored section – total width of bore before walls 2m

  2. Cut and cover section – finished span not exceed 1.6m

Working with these limits means a full risk assessment was completed, see Risk Assessment. The outcome was that a the tunnel with a minimum internal width of 1.5m based on a maximum stock width 0.7m would be completely safe, as it allowing for passenger to detain and safely walk past in an emergency. This does mean it is possible for person to reach the side of the tunnels, therefore, as per PCMR warning signs are displayed at the station and at the tunnel entrance.

The L&YT will become a loco shed and to allow sufficient room on the approach to KT for an access only line, L&Y Shed Siding, to be built, the timber car park retaining wall has been rebuilt, see Retaining Walls.

Tunnel construction

The cut and cover tunnel is constructed from of 6” solid blocks, 3 blocks thick of 8 courses, with two courses of 9” hollow blocks also 3 thick to allow keying into the roof. The tunnel roofed with a propriety concrete floor designed to carry 38 tonnes which is fully keyed into the hollow blocks. Where vehicle traffic crosses the inverted ‘T’ beams are laid adjacent to each other. The first 2m of the tunnel is fenced and carries a small garden are, so use ‘T’ beams and blocks.

The bored tunnel is constructed of a single horizontally laid solid block wall. The roof of the tunnel is formed with 150x100mm pre stressed concrete lintels which are cemented to the underside of the existing 300mm foundations tying both tunnel and toilets into one structure.

The portal extension is also single horizontally laid block wall. Currently it is unroofed due a shortage of funds. It is planned to add a suitable roof which will provide a pedestrian route into the Dell.

The tunnel complies with the main functional requirements of PCMR but is will require warning signs due to width restrictions.

Fencing

All significant drops to which passengers may have access are fenced with a double rail 50mm steel fencing. Where the fence is directly next to drop wire mesh has been added to increase safety.

Retaining Walls

On the approach to KT existing walls have been removed and replaced by new block walls at a suitable minimum distance from running lines.

Train Safety KT

The risk assessment identified the following requirements to ensure safe passage of trains through the KT: -

  1. The operating procedures required reviewing and simplifying.

  2. Fully signaling required for the section including the KT. This was provided previously for the L&YT. The system has been modified with additional signals and sections on the KT&DD.

  3. Rear trains lights. Previously there was no requirement with the operating procedure for tail lamps unless operating in the dark. However, due to the length of KT this has been amended to require all trains to display a tail lamp even during daylight running.

  4. Emergency lighting. Due to the limited light within KT emergency lighting is provided. It is operated automatically in the event of a power cut or by means of an emergency rope operated switch. The operation of the emergency light has been added to the operating procedures.

  5. Internal combustion engines. Due to the potential of operating within a confined space the operating procedures now require that any locomotive with an internal combustion the engine must have its engine be turned off if stationary within the KT.

Train Safety Dell Deviation (DD)

The DD is provided with full automated signalling utilising a mixture of treadle and track circuits to separate trains. It is broken into 3 sections, level crossing to Dell end of KT, Dell end of KT to mid Dell straight and mid Dell straight to Loop entrance selection buttons.

Speed Limit For Ground Level Track

Previously the general speed limit was 8mph for the ground level track. The revised operating procedures have reduced this to 6mph with the exception of areas which have a signed lower limit which is normally 3mph.

Due to the nature of the track work in areas off the mainline, eg, in sidings, all movements should be undertaken at a ‘Dead Slow’ pace.

Risk Assessment

Definitions

Standard risk assessment process using an 8 by 8 matrix below has been used, with the following definitions: -

Severity

Score

Key

No action required

Action should be taken reduce risk where possible

Action required immediately

Risk Assessment Scores

Operating Procedures Ground Level Track (Revised 1 April 2017)

1

The full set of safety assessments must be completed before public running. All problems should be rectified and a record made on the running log.

2

The Track Marshal is responsible for the safe operation of the railway.

3

All members present are responsible for the safety of all visitors to Ravensprings. Any potential problems or hazards should be brought to the attention of a Track Marshal. If safety is in doubt immediately stop all operations.

4

Drivers under instruction must not drive when members of the public are present. At other times they must be under the close supervision an authorised driver.

5

When public are present all operating staff, must meet the insurance company's minimum age, currently 16.

6

Locomotives must have:-

(i)

(If steam) a current boiler certificate and spark arresting device fitted.

(ii)

Have a secondary coupling between the loco and the driver’s sitting position.

(iii)

Suitable audible warning device (Whistle)

(iv)

Ground level trains must display a tail light.

7

Visitors may use all the running facilities provided that: -

8

(i)

They have been approved by the Track Marshal

(ii)

They have signed the visitors book

(iii)

Their locomotive meets the requirements in 6.

(v)

Are aware of these rules.

9

All operating staff must be aware of signal positions and their meanings.

10

Whistles should be sounded:

(i)

Before train movements.

(ii)

Before entering and when leaving a tunnel.

(iii)

To give warning if persons are near running line.

(iv)

In the event of emergency short sharp blasts on a whistle should be sounded.

11

When formed up a train must have:

(i)

A guard when carrying members of the public, except where the train is made of only one carriage, when the driver assumes the guard's responsibilities.

(ii)

A rear red tail light

(iii)

Suitable and sufficient braking system to ensure they can stop when driven at track speed limits.

12

Trains must not stop in the Kitson Tunnel unless it is an emergency, in which case the following applies:

(i)

The lights should be turned on for public safety and then reset to running once train ready to move.

(ii)

Internal combustion engines must be switched off if train is stationary.

13

Any locomotive or rolling stock which has been derailed should be taken out of service for examination. The track in the area of the derailment should also be inspected to ascertain the cause. Noted in running log.

14

It is the responsibility of the driver to stay at the controls and ensure safe operation of the loco.

15

The maximum speed limit is 6mph except where signs indicate lower speeds.

16

The driver must not start the train until given the right-of-way by the guard.

17

The role of the guard is to:

(i)

Ensure passengers board, ride and alight safely.

(ii)

Give 'right of way' when safe to do so

(iii)

In the event of an emergency/breakdown protect the rear of the train.

Signals

Green colour light or semaphore off

Proceed at suitable speed for your train.

Yellow colour light or distant semaphore on

Proceed with caution preparing to stop as next signal is at danger, note L&Y distant signal is red not yellow.

Red colour light or semaphore on

STOP do not pass

Red colour light or semaphore with 'Stop and select to proceed'

Press appropriate button do not proceed until 'Green/Yellow' and/or semaphore is off


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