Modern Railways – April 2019

74 Modern Railways April 2019 http://www.modern-railways.com

which will enable the safe distance between trains

to be reduced, aiding the possibility of frequency

improvements. The ability to take advantage of

improved acceleration is limited to an extent by

passenger comfort, but Thales is to re-map the

speed profile of the DLR, meaning trains will be

able to travel faster for a greater length of time.

INFRASTRUCTURE CHALLENGES

When the DLR was built in the 1980s, the

infrastructure and trains were designed together,

so the railway was effectively built around the

original P86/P89 fleet. This, combined with the

light rail specification, led to the network having a

number of tight radius bends and reverse curves.

While the current vehicles of just under

30 metres in length can manoeuvre well on these,

having full-length walkthrough trains presents

challenges, particularly concerning end throws

and centre throws of the vehicles. TfL therefore

approached manufacturers seeking solutions

to how this issue could be overcome. The most

severe 40-metre reverse curve at Poplar is not

normally used in passenger service, but there

are a number of other tight spots on the system.

The tight curves also create challenges for ride

quality – the new trains will have the same wheel

profile as the current fleets, which is designed

to work on tight corners but does not ride so

well on straight sections. Newer technology will

provide a more comfortable ride for passengers.

Platforms are another aspect of the DLR

designed around the existing trains, where the

challenge is to comply with the Rail Vehicle

Accessibility Regulations (RVAR) which specify

a maximum stepping distance of 70mm.

TfL has commissioned Omnicom, part of

Balfour Beatty, to carry out a gauging study of the

DLR network. This will involve lasers being fitted

to a train to create a point cloud study of the

network to verify gauging standards. The study

will give manufacturers a clearer picture of the

gauging requirements. The tightest clearances

are found in the tunnel between Shadwell and

Bank, which was built to a smaller diameter

(4.8 metres) than others on the system, and the

Omnicom survey will verify the limitations here.

The steepest gradients on the DLR are 6%,

found on the ascent out of the Bank tunnels and

between Poplar and Blackwall. The specification

mandates that new trains will be able to

rescue both their counterparts and existing

trains, even on these steepest of gradients.

SIGNALLING UPGRADE

The DLR was built with a GEC Alsthom

inductive loop, fixed block signalling

system and was subsequently retrofitted

with a Thales Seltrac system.

During 2018 the Vehicle On-Board Controllers

(VOBCs) were upgraded with new faster

processors. This is the same processor used for

the Thales signalling system on the London

Underground Jubilee and Northern Line fleets

and as part of the Four Lines Modernisation

(4LM) programme for the sub-surface lines.

Coupled with the arrival of the new DLR

fleet will be the introduction of the Thales

On-Board Platform (TOP) signalling system,

with the chief advance being an upgrade to

the VOBC, fitted with a much more powerful

processor; these will operate alongside the

upgraded VOBCs fitted in the B2007 fleet.

Tests are taking place with the upgraded

equipment on the existing stock first of all,

with close collaborative working between

TfL, DLR operator KeolisAmey and Thales. In

respect of the new fleet, the equipment will

first be tested at the winning manufacturer’s

facilities to ensure it will successfully integrate

with the new train prior to its use on the DLR.

ON-BOARD FACILITIES

The new DLR fleet will bring a range of on-board

improvements in the passenger environment.

Real-time customer information systems

will be much more easily configurable than

those on the current fleet; as well as providing

information on service disruption on the DLR

and other TfL networks, tailored messages could

be shown. The system will utilise TFT screens,

Glinting in the winter sun: a DLR service departs from

London City Airport on 24 February 2016. Antony Guppy

Set for expansion: B2K set Nos 96 and 97 sandwich B92 set No 62 in the extension to the main maintenance shed

at Beckton depot on 7 April 2017; the site is to be further enhanced to accommodate the new fleet. Antony Guppy

073-077_MR_Apr 2019_DLR.indd 74 12/03/2019 15:08