Prague’s Škoda 15T trams set for long-awaited AC upgrade

Prague’s distinctive Škoda 15T trams, a backbone of the Czech capital’s public transport network, are set to become significantly more comfortable as the city moves ahead with plans to retrofit the remaining non-air-conditioned vehicles with modern cooling systems.

Major retrofit to cool Prague’s tram backbone

Publicly available information shows that the Prague Public Transit Company has signed a contract to install air conditioning in 123 Škoda 15T trams that currently operate without onboard cooling. The multi-year project targets vehicles delivered in earlier production series, which were supplied without full-vehicle air conditioning and have since gained an unwelcome reputation among riders during Central Europe’s increasingly hot summers.

The 15T, also marketed as Škoda ForCity Alfa, is a 100 percent low-floor tram specifically developed for Prague’s historic and often sharply curved tram network. Over the past decade it has become the city’s most visible modern tram type, deployed on many high-frequency routes across the center and inner districts. Until now, only later series units have offered full passenger-compartment air conditioning, while earlier cars relied mainly on natural ventilation through opening windows.

Reports indicate that three independent air-conditioning units will be installed on each retrofitted tram, with one unit serving each articulated section of the vehicle. The upgrade, valued in the hundreds of millions of Czech crowns, is planned as a staged program so that large parts of the fleet can remain in daily service while individual trams are withdrawn in rotation for installation work.

Once the program is complete, Prague’s entire 15T fleet is expected to offer a consistent, climate-controlled interior, narrowing the comfort gap between older and newer rolling stock and responding to years of passenger complaints about overheated cars in peak summer conditions.

From policy decision to signed contract

The decision to equip all Škoda 15T trams with cooling has been under discussion in Prague for several years. Earlier city documents and press materials show that the intention to “complete air conditioning” of the 15T fleet was endorsed at the municipal level in the late 2010s, but a combination of procurement questions, technical preparation and budget priorities slowed concrete progress.

Transport-focused outlets in the Czech Republic have reported that an initial tender for the retrofit was launched and later canceled, after it became clear that the project specification would heavily favor the supplier of existing systems already in use on air-conditioned 15T units. A revised approach was subsequently prepared, opening the way for a competitive procedure and the eventual selection of a specialist supplier to deliver, install and integrate the new equipment.

According to recent coverage, the successful contractor is a Polish company providing power electronics and HVAC technologies for rail vehicles. The agreement, reported at a value exceeding 395 million Czech crowns, covers the design adaptation, delivery of rooftop units, related electrical systems and control software, as well as testing and certification on the Prague network.

Project timelines published in local media suggest that the retrofit will be carried out gradually over roughly six years. This schedule reflects both technical complexity and the operational need to maintain sufficient tram availability on key routes while individual vehicles are cycled through workshops for modification.

Passenger comfort and tourism implications

For daily commuters and visitors alike, the upgrade is expected to significantly change the travel experience on some of Prague’s busiest tram lines. During recent heatwaves, passenger feedback shared in local forums and community channels has frequently labeled non-air-conditioned 15T trams as “mobile saunas,” highlighting interior temperatures that can exceed those on the street when vehicles are crowded and windows offer only limited relief.

With Prague positioning itself as an attractive year-round city-break destination, consistent comfort on public transport is increasingly viewed as part of the broader visitor experience. Trams are not only a transport mode but also a moving showcase of the city, passing many of its best-known landmarks. Cooling in all 15T vehicles is therefore likely to be welcomed by tourism operators, hotels and event organizers who frequently recommend tram routes to guests as an easy way to explore central districts.

The retrofit also aligns Prague more closely with passenger expectations in other major European cities, where air conditioning has become standard on most new-generation light rail and metro fleets. As climate models indicate more frequent and intense summer heat events across Central Europe, urban transport operators are under growing pressure to ensure vehicles remain usable and comfortable even during prolonged hot spells.

For families, older passengers and travelers carrying luggage, a stable on-board climate can influence route choice, making tram travel more attractive compared with private cars or ride-hailing services. In turn, this can support the city’s wider goals of reducing congestion and emissions in the historic core.

Technical and operational challenges of retrofitting

Retrofitting air conditioning to an existing low-floor tram design presents both engineering and operational challenges. Unlike new-build vehicles designed around HVAC equipment from the outset, earlier 15T series must accommodate additional weight, power demand and rooftop hardware within a structure already optimized for Prague’s often tight bridges, tunnels and overhead line clearances.

Technical materials from Škoda Group underline that air-conditioning systems for rail vehicles must balance cooling performance with energy efficiency and reliability in demanding, stop-and-go urban service. For the 15T retrofit, this means integrating new units with the vehicles’ electrical systems, ensuring that cooling does not unduly affect traction power availability, and that maintenance remains manageable within existing depot facilities.

Operationally, the transit company faces the task of scheduling workshop time for 123 trams without undermining daily service frequencies. Each vehicle will require removal of interior fittings, installation of cable runs and control units, structural preparation on the roof, placement of the AC modules and comprehensive functional testing. This work must be coordinated with regular heavy maintenance cycles to minimize additional downtime.

There is also a human factor: on already air-conditioned units, public information campaigns have encouraged passengers to keep windows closed so that the cooling system can operate effectively. With more of the fleet gaining AC, the operator is expected to continue educating riders on how best to use the upgraded trams, particularly during the first hot seasons when habits formed on non-cooled vehicles may persist.

Part of a wider modernization of Prague’s tram fleet

The 15T air-conditioning project is only one element of a broader modernization of Prague’s tram network. In parallel, the city is introducing a new generation of Škoda 52T trams, which are equipped from the factory with full-vehicle air conditioning using an environmentally friendly refrigerant, along with updated passenger information systems and refined bogie designs.

By combining retrofits on existing 15T vehicles with deliveries of fully modern 52T trams, Prague is seeking to raise the baseline comfort level across the tram system rather than on a limited number of flagship routes. Over time, this should reduce the variability passengers experience today, where a cooled vehicle may be followed by an older, far warmer tram on the same line.

Industry observers note that similar retrofit programs have been undertaken in other European cities, but Prague’s initiative stands out by the sheer number of vehicles involved and the importance of trams in the city’s overall transport mix. With more than 900 trams of various types in operation, and the 15T forming a large share of that figure, the success of the upgrade will be closely watched by other networks facing comparable climate and budget pressures.

As installation work begins and the first retrofitted vehicles re-enter service, riders can expect a gradual but noticeable change. Over several summers, previously stifling journeys on older 15T trams should be replaced by consistently cooler rides, reshaping the daily experience of public transport across Prague’s historic streets.