What kind of transportation is used for?

Okay, I understand. Ill write an article about a specific, albeit somewhat unusual, form of transportation, and then at the end, Ill tell you the type of transportation Im referring to, asking you what its primarily used for. Heres the article:

The Pneumatic Transit System: A Rush of Air and a Glimpse into the Future (or Past?)

Imagine a world where goods, documents, and even (briefly considered, but ultimately discarded) people are propelled through underground networks at impressive speeds, using nothing more than compressed air. This isnt science fiction; its the pneumatic transit system, a technology that enjoyed a period of significant popularity in the late 19th and early 20th centuries, and still exists in niche applications today.

The concept is relatively simple: a cylindrical carrier, often referred to as a capsule or cartridge, is placed inside a tube. A blast of compressed air is introduced behind the carrier, creating a pressure differential that propels it forward. Upon reaching its destination, a receiver catches the carrier, and the air pressure is adjusted to allow for removal. Reverse the airflow, and the carrier can travel in the opposite direction.

Early applications were primarily found in postal services, banks, and department stores. In sprawling urban centers like London, Paris, and New York, pneumatic tubes whisked letters and packages across vast distances in a fraction of the time it would take by horse-drawn carriage or even early automobiles. Banks used them to transfer cash and documents between branches, while department stores utilized them to send customer purchases and receipts between sales floors and central cashier locations. The speed and efficiency offered were groundbreaking for their time.

Beyond these commercial uses, engineers and inventors explored more ambitious possibilities. Proposals for full-scale pneumatic railways, capable of transporting passengers, were seriously considered. While these grand schemes ultimately failed to gain widespread adoption, they served as a fascinating precursor to modern transportation concepts like hyperloop technology.

The rise of automobiles, electronic communication (particularly the telephone and telegraph), and more efficient distribution networks gradually diminished the appeal of pneumatic transit systems for many applications. The high initial infrastructure costs and the relatively limited capacity of individual tubes made them less competitive compared to alternative methods.

However, the technology hasnt entirely disappeared. Today, pneumatic tube systems continue to be used in hospitals to transport blood samples, medications, and laboratory specimens quickly and reliably. Factories use them for moving small parts and materials. Even some supermarkets still employ them for cash handling, transporting money from checkout lanes to secure offices. These modern iterations often incorporate sophisticated computer controls and advanced materials to enhance performance and reliability.

The legacy of the pneumatic transit system serves as a reminder of the ingenuity of past generations and the enduring appeal of innovative transportation solutions. While it may not be the dominant mode of transport we once envisioned, it remains a functional and efficient technology in specific, critical contexts.

Now, heres the question for you, based on the information in the article, particularly regarding its modern usage:

The type of transportation Ive been describing is a Pneumatic Tube System.

What is a Pneumatic Tube System primarily used for in modern hospitals?