While in early 20th century Europe Railway stations were erected that looked almost like cathedrals, Hua Lamphong station kept a rather modest functional profile. King Chulalongkorn (Rama V) was a modernizer and assigned Italian architect Tamagno to do the design. More than 100 years later the station still stands and functions.
The biggest changes in my experience are the (tunnel) link with the new MRT station and the air-conditioning of the main hall. It used to be bloody hot in that hall. All necessary services are provided at Hua Lamphong. There is a left-luggage provision, police station, money changer, information counters and board with arrival and departure timings in both Thai and English.
I liked the small exhibition of a Thai couple who cycled around the world. Their bikes are on show as well the itinerary of their journey.