How to change batteries on a Metro system

Metro systems are designed so batteries can be changed without switching off the signal head. By replacing one battery at a time, the remaining batteries continue to power the system during the swap.

Before starting, identify which signal heads need their batteries replacing. We recommend changing batteries in manageable groups, rather than replacing every battery across the whole site at once. This reduces manual handling and makes battery swaps easier to manage.

Before you start

Make sure you:

• Have enough fully charged batteries for the signal heads you are working on.
• Use the correct battery type recommended for the system. Do not mix different battery types.
• Keep charged and depleted batteries clearly separated so they cannot be mixed up.
• Check the battery cables and connections for any signs of damage.
• Plan how the batteries will be moved around the site. Each battery weighs approximately 20 kg, so we recommend using a suitable manual handling aid.

How to change the batteries

At each signal head, replace one battery at a time. Do not disconnect all of the batteries together, as this could remove power from the signal.

Remove one depleted battery and replace it with a fully charged battery. Make sure it is connected correctly before moving on to the next battery.

Repeat this process until the required batteries have been replaced.

A Metro unit can hold up to six batteries. In most cases, we recommend using two or four batteries, as this helps make future battery swaps more manageable.

Check the batteries after the swap

Once the batteries have been replaced, check that the new batteries are being recognised by the system.

You can check the battery voltage reading using either:

• the unit controller at the signal head, or
• the master controller on site.

Check that the reading has updated before moving on to the next signal head.