Macの列車Wi-Fi：使えるようにするか、自分のテザリングに切り替える

Train Wi-Fi usually reaches the internet over mobile networks along the track. All the passengers share that connection, so it is often slow.

Applies to: All current macOS versions. Instant Hotspot needs an iPhone or a cellular iPad with the same Apple Account as the Mac.確認日：2026年10月29日

症状

  • The Mac joins and signs in, but pages load slowly or not at all.
  • Calls freeze and uploads stop.
  • The connection drops in tunnels and between stations, then comes back.
  • The sign-in page appears again after some time.

考えられる原因

  • A shared connection. The train's connection serves all its passengers. A full train leaves little speed for each device.
  • Gaps in mobile coverage. Tunnels, cuttings and rural areas interrupt the mobile networks that the train uses.
  • Limits from the operator. Some operators limit the speed, the data or the time for each device. Some block streaming.
  • The sign-in, a VPN or custom DNS. Train Wi-Fi often has a sign-in page. A VPN or custom DNS can hide it, as on other public networks.
  • Background data on the Mac. Sync, backups and updates use the same small connection as your work.

確認方法

  1. In a browser, open http://captive.apple.com. If the operator's page opens, sign in.

  2. Run Apple's speed test. Write down the result.

    networkQuality

  3. 今ネットワークを使っているプロセスを確認します。止めるにはqを押します。

    nettop -P -d

  4. Look at the mobile signal on your phone. Strong signal and few passengers can make the hotspot faster.

解決方法

  1. Turn on Low Data Mode for the train network. Choose Apple menu > System Settings > Wi-Fi.

  2. Click Details next to the train network. Turn on Low data mode. Click OK.

  3. Pause sync, backups and updates until you are on a better network.

  4. In calls, turn off your camera. Audio uses much less of the connection.

  5. If the train Wi-Fi is too slow, click the Wi-Fi icon. Choose your iPhone under Personal Hotspot.

  6. Run the same speed test on the hotspot. Keep the faster of the two.

  7. To stop the Mac from going back to the train Wi-Fi, open its Details. Turn off Automatically join this network.

  8. On the hotspot, pause the apps that use data in the background. See Mac uses Personal Hotspot data in the background.

  9. In tunnels and remote areas, the hotspot can drop too. Save your work before them.

Kilobatを使う場合

  1. Find which part is slow: Wi-Fi, the router, the internet, DNS or the sign-in page.

    kilobat diagnose

  2. Check the sign-in page, and whether the network logged you out after an earlier sign-in.

    kilobat portal

  3. Test the speed with a limit on the data that the test uses.

    kilobat speedtest --budget-mb 10

  4. アプリごとのアップロードとダウンロードをリアルタイムで確認します。止めるにはqを押します。

    kilobat status --watch

  5. Mark the train network as metered. Kilobat then treats it like a hotspot.

    kilobat networks cost metered

  6. For travel data packs, see Working from anywhere with a Mac: eSIMs, phone hotspots and making data last.

よくある質問

Is train Wi-Fi or my hotspot faster?

It depends on the route, the time and your carrier. Test both with the same test, then keep the faster one.

Does train Wi-Fi use my phone's data?

No. Train Wi-Fi does not use your data plan. The Personal Hotspot does.

Is train Wi-Fi safe for work?

Pages with https hide their contents from the network. Turn on a VPN after you sign in, if your work needs one.

出典

2026年10月29日に確認。