Recorded announcements are a feature of almost all modern
trains and live intercom broadcasts have been an integral part of public
transport for decades. It is vital that those with a hearing impairment are not
denied the ability to receive this information, but the construction of modern
carriages has proved a barrier. Ampetronic, the leading UK based audio
induction loop manufacturer, set about finding the solution.
Although modern reinforced concrete buildings provide plenty of
challenges for induction loop installers, the vibration and greater percentage
of metal in a moving railway carriage is a much sterner test. Working in close
conjunction with South Korean manufacturer Inter-M, Ampetronic’s XA88 ‘Loop
Driver’ has been developed to bridge the technology gap for reliable induction
loop systems in public transport vehicles.
Two main challenges faced the project. The first was to make a
loop amplifier rugged enough to be able to work perfectly despite inherent
vibration of a moving vehicle. The second was overcoming the significant signal
loss of induction loops installed in vehicles made primarily of metal that
interferes with the magnetic field produced by the loop and is picked up by
These challenges were met by
using very strong, high quality components. Featuring military-grade connectors
and a heavily ruggedised case, the XA88 delivers a typical output of 11A RMS,
features two fully isolated, balanced inputs from line level sources or
loudspeaker systems and can be built for 110v or 24v DC power supply.
“We did a considerable amount of surveying and testing in similar
existing trains and in a part-built carriage at Hyundai-Rotem’s works. By
careful analysis of experiments with where to position the loop, we came up
with a practical configuration and a suitable high current which together
almost entirely mitigate the effects of metal loss,” says Ampetronic’s Tom
The first XA88 units were successfully fitted to a new fleet of 48
Matangi class suburban electric trains, being manufactured by Hyundai-Rotem in
South Korea for Greater Wellington Rail Ltd, serving suburban routes around New
Zealand’s capital city Wellington.
To further confirm the effectiveness of the XA88 solution, Ampetronic
have also assisted a project involving
LUAS, the Rail Procurement Agency (RPA) and ALSTOM to install the system
on 66 LUAS trams in Dublin, Ireland.
The testing of the LUAS Tram system was attended by Ireland’s
former Minister for Transport , John Moloney , CEO of the RPA, Frank
Allen and DeafHear ’s Julianne Gillen and Michael Tighe.
Julianne was “impressed with the consistency and clarity of the
loop” and reports that it is still working well, whilst to illustrate the
problem that exists for the hard of hearing on public transport, after the
tests Michael reported that “I never knew stations were announced before I did
the loop testing”.
It is hoped that by developing the XA88, Ampetronic have provided
technology that means there is now no reason why announcements on trains,
trams, metros and buses cannot be just as available to anyone with a hearing
impairment as they already are at ticket offices, stations and terminal
Pictured are Julieanne Gillen of DeafHear; former Junior Minister for transport, John Moloney
(red stripped tie); and CEO of the Railway Procurement Agency, Frank Allen (Pictures
courtesy of RPA, Ireland).
11 June 2021
7 May 2021