Here’s a refined and engaging version of your information, suitable for a history feature or educational write-up:

On the Bombay, Baroda and Central India (BB&CI) Railway—headquartered in Bombay (now Mumbai, Maharashtra)—some passenger coaches had an ingenious cooling system:

Double-walled compartments lined with lead-zinc sheets

The space between the walls was filled with ice, providing rudimentary air cooling

This was a creative, mechanical solution before electric air-conditioning became available

The Frontier Mail was the first Indian train to be equipped with air-conditioned (AC) coaches

Year Introduced: 1934

Route: Originally ran between Bombay (Mumbai) and Peshawar (pre-Partition)

Now renamed as the Golden Temple Mail, it connects Mumbai and Amritsar, Punjab

The AC coaches marked a major milestone in luxury train travel, bringing comfort during long journeys through India’s tropical climate

One of the oldest and most prestigious trains in India

The introduction of AC marked the beginning of modern onboard amenities in Indian Railways

Its name change to Golden Temple Mail reflects the cultural and religious importance of its northern terminus at Amritsar.