Fear you are going to melt every time you step on the Tube? Well if you ever use the Piccadilly line you can celebrate because Transport for London (TfL) is buying a host of new fully air conditioned trains.

There will be 94 new trains for the Piccadilly Line - but with all these things there is a catch. Regular passengers on the delay-hit line will be frustrated to hear they won't be in use for another four years.

From 2023, the Tube line will start receiving Siemens Mobility trains to replace the 1970s existing stock.

The announcement comes afterf rush hour difficulties on the Tube line, which runs from Uxbridge and Heathrow Airport in the west to Cockfosters in the east.

The £1.5 billion contract between London Underground and the German trainmaker will see dozens of trains delivered in total.

Around 700,000 people use the Piccadilly line every day, serviced eventually by a train every 135 seconds at peak times. TfL hope that would mean an extra 21,000 passengers can board the trains every hour.

Crucially, the trains will include air conditioning, as will the Central, Bakerloo and Waterloo & City lines, as part of the Deep Tube Improvement program, with further contracts to be issued later, and an estimated 250 new Tube trains coming to the capital.

Capacity across all four lines is expected to increase by 36% by 2035. Meanwhile London's population is expected to increase by more than 20% to 10.8 million by 2041.

Don't the new Piccadilly line trains look fancy!

The contract for the Piccadilly line Tube trains is being awarded with the expectation that the same trains will be ordered for the other three Deep Tube lines.

Sabrina Soussan, CEO of Siemens Mobility, said "Our new metro trains for London will significantly increase capacity and frequency on the Piccadilly line.

"At the same time, they will offer tube users substantially improved passenger experience.

"Our services will support London Underground over the trains' full lifecycle to ensure that they serve the London public with the highest reliability and availability."

Nigel Holness, Managing Director of London Underground, said: "The introduction of new trains on the Piccadilly line will significantly improve the journeys of millions of our customers, providing more frequent and more reliable trains for decades to come.

"This order will mean the replacement of the 1970s Piccadilly line fleet, with delivery of the new trains starting in 2023, and will help address crowding on the line as London's population continues to rise."

What will the new trains be like?

The current Piccadilly line stock dates back almost 50 years and struggles to cope with the demands of today's Tube network with frequent delays and cancellations to services.

The new trains will be six-metres longer and include walk-through carriages, like the District, Metropolitan and Circle line trains. Carriages will also be fully air conditioned.

The old Piccadilly line trains date back to the 1970s and are blighted by delays and cancellations

Previously, the possibility of driverless trains on the Tube line was raised, although speaking in June, TfL said they would keep an operator on board the trains.

A TfL spokeswoman said: "We have no current plans for driverless trains.

"Our next generation of trains will be introduced with an operator on board.

"Given they will start to be introduced in the mid-2020s, and will last for at least 40 years, it makes sense to ensure they are future proof and can support the latest automatic technology.”

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