Yes, you can absolutely use your laptop on a train, and for many travelers, it is the preferred "mobile office" due to the stability and space compared to airplanes. Most modern long-distance trains (like Amtrak in the US, the TGV in France, or the Shinkansen in Japan) provide seat-back trays or larger fold-out tables in "table seats." Furthermore, most high-speed and commuter lines now offer free Wi-Fi and individual power outlets (usually 110V or 230V) located near the window or under the seat. However, there are caveats: Wi-Fi can be spotty in tunnels or rural areas, and on older "regional" coaches, power outlets might be missing entirely. It is also wise to use a privacy screen in crowded cars. While generally safe, you should never leave your laptop unattended when visiting the cafe car or restroom, as opportunistic theft can occur on even the most high-end rail lines.