Boxcar uses Web Sockets to communicate with the server. Unfortunately not all browsers currently support this technology. Below is a list of browsers and the their respective minimum version that do support Web Sockets (see http://caniuse.com/#feat=websockets)

Browser List:

Internet Explorer: V10
Windows Edge: V12
Firefox: V42
Chrome: V45
Safari: V9
Opera: V34
IOS Safari: V8.4
Opera Mini: Not compatible
Android Browser: V4.4
Chrome Android: V47