---
title: "Train Wi-Fi slow on Mac: test it, save data or use your hotspot · Kilobat Guides"
url: "https://kilobat.app/zh-hant/guides/train-wifi-mac"
description: "Train Wi-Fi is shared by many passengers and drops along the route. Test it, get more from it, and know when your phone's hotspot is the better choice."
---

# Mac 上的火車 Wi-Fi：讓它能用，或改用你的熱點

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. · 檢查日期：2026年10月29日

## 症狀

- 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.

## 可能原因

- **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.

## 如何檢查

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. 查看目前有哪些處理程序在使用網路。按 q 停止。

   ```
   nettop -P -d
   ```
4. Look at the mobile signal on your phone. Strong signal and few passengers can make the hotspot faster.

## 如何修正

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](https://kilobat.app/zh-hant/guides/hotspot-background-data).
9. In tunnels and remote areas, the hotspot can drop too. Save your work before them.

## 使用 Kilobat

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. 查看每個 App 的即時上傳和下載。按 q 停止。

   ```
   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](https://kilobat.app/zh-hant/guides/work-from-anywhere-mac-mobile-data).

## 常見問題

**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.

## 資料來源

- [Apple Developer 新聞：How to modernize your captive network（2020年6月22日）](https://developer.apple.com/news/?id=q78sq5rv)
- [Apple 支援：Mac 上的 Wi-Fi 設定](https://support.apple.com/guide/mac-help/wi-fi-settings-on-mac-mh11935/mac)
- [Apple 支援：連接 iPhone 或 iPad 的個人熱點](https://support.apple.com/en-us/111785)
- [Apple 支援：使用「即時熱點」連接你的個人熱點](https://support.apple.com/en-us/109321)
- [Apple Developer：NWPath isExpensive](https://developer.apple.com/documentation/network/nwpath/isexpensive)
- networkQuality(8) and nettop(1), man page installed with macOS 27.2

查核日期：2026 年 10 月 29 日。

## 相關指南

- [Mac 在背景使用個人熱點流量](https://kilobat.app/zh-hant/guides/hotspot-background-data): 連上手機熱點的 Mac，可能在你什麼都沒做時用掉大量流量。
- [Mac 上看不到 iPhone 熱點](https://kilobat.app/zh-hant/guides/instant-hotspot-not-showing): 「即時熱點」讓 Mac 不必輸入密碼就能加入你的 iPhone 或 iPad 熱點。
- [使用 Mac 隨處工作：eSIM、手機熱點與節省數據](https://kilobat.app/zh-hant/guides/work-from-anywhere-mac-mobile-data): Mac 使用行動數據時，可能在幾天內用完旅行數據包。
- [讓 Mac 把網路視為計量網路](https://kilobat.app/zh-hant/guides/metered-network-mac): macOS 會把某些連線標記為高成本，例如 iPhone 個人熱點。
- [在 Mac 上使用「低數據模式」](https://kilobat.app/zh-hant/guides/low-data-mode-mac): 「低數據模式」會讓 macOS 和 App 在某個 Wi-Fi 網路上少用一點流量。
- [Mac 上沒有出現 Wi-Fi 登入頁面](https://kilobat.app/zh-hant/guides/captive-portal-not-appearing): 公共網路通常會攔住所有流量，直到你在登入頁面上登入。
- [Mac 上的視訊通話卡頓或凍結](https://kilobat.app/zh-hant/guides/video-call-stutter-mac): 通話需要的是穩定的延遲和穩定的上傳，而不是高速。