London Banter - View Single Post - Top up Oyster Prepay

Paul Corfield · September 7th 04, 07:01 PM posted to uk.transport.london

On 7 Sep 2004 02:15:34 -0700, (Graham
Hick) wrote:

This happened to me last night and I was wondering if anyone
else had come across it. I was topping up my Oyster pre-pay
card at the touch-screen ticket machine at North Greenwich,
using up all the small change in my wallet. After about £7,
the machine closed the coin slot, and threw all my coins back
into the rejected coins/change tray. It sounded like I'd won
the jackpot at Las Vegas!
[snip]
Not a major grumble, but a bit of a "head scratcher" - why was
this feature designed into the system in the first place?

as others have said there is a holding unit called an escrow that
retains your inserted notes or coins until the transaction has fully
completed. Obviously these units have a limited capacity and your volume
of coins tripped the unit out thus returning your coins to you.

Once a transaction is successfully completed the coins are moved from
the escrow either to the vault or to the change tubes in the machine.
The machine knows how much is in each tube and what needs to be kept to
try to maintain change levels.
--
Paul C

Admits to working for London Underground!