Why don't trains (especially passenger) have some sort of GPS in the cab?

Modern trains DO use GPS - in the UK at least. However, GPS is not much good for telling the drivers where they are: the whole point of 'route learning' is so that they know where they WILL be in the next few minutes so that they can take into consideration up-coming speed restrictions, junctions, stations etc. etc. What the GPS does is tell the train's computer exactly where it is. This information is used for fault reporting and so on. One of its features is that it will, for example, prevent the driver/conductor from opening the passenger doors on the 'wrong' side of the train or, indeed, if the train is not actually in a station.

We already have it on many locomotives. The Union Pacific calls it trip optimizer. When the locomotive is equipped with it, the computer will run the train in regards to power and dynamic brake. The engineer enters his track warrant number into the system and enables it. It will even slow the train down for speed restrictions. It will not apply the train brakes though. That will change when PTC gets implemented in the near future. Personally, I don't like trip optimizer at all. As a long time engineer, I don't like a computer deciding how to operate a train for me. In addition all the new locomotives have GPS so the railroad can track where and what a locomotive is doing.

WTF, the train moves on fixed tracks. kinda got to go where they go. Why GPS?

NEW Locomotives/Trains DO


GPS tells you where you are. It does not see the tree blown across the track . They do now have systems that locate the train and can search out for things like an allowed train speed and the system adjusts the speed.
You make it sound like remembering a train route is like driving a car with many options to turn every few hundred yards at the next corner.
They DO NOT memorize EVERYTHING they do know a lot. Just knowing where they are is just a small part of it.
The weight and length of train for freight. An express or local passenger train.

I would much rather have the Engineer paying attention then depending on the machine to do things and they just read a book and eat their lunch in the front seat enjoying the scenery. Mechanical things and electronic things can malfunction. Nice to have a Human that knows what he is doing in case of a malfunction.

There are train systems that operate without a driver in the Front seat.
https://www.youtube.com/watch?v=e1gE4aoJRw0

A GPS unit cannot help a Passenger in distress.
https://www.youtube.com/watch?v=kD9Wks3bZSM

https://www.youtube.com/watch?v=a52ZSCIAoRk

The extreme high speed train depend on it as the driver cannot see far enough ahead.

There has been driver less "train cars" for many many years. Maybe you should research Morgan town Their system has no drivers and was built in 1970. Not really a train but works similar to one.
https://www.youtube.com/watch?v=Dm31tZsnqhE

Yeah the driver kinda does need to know everything about the routes they sign. Stations, speeds, signals, junctions, level crossings, controlling signaller for the section, gradients, notable features, areas of low rail adhesion, all kinds of route risks, which signals they can and cant accept for the route to stay on course and many more things. It's all in the drivers head through route learning and signing for the route to state they are confident/competant. Gps is merely so controllers can locate your train and record every action the driver takes. It would be pointless being the same as one in your car. Hope that helps.

On train tracks there are speed limit signs and warning signs. The signals tell the driver when to stop and the signals set the route.
Trains do not get lost.

You mean so the Engineer knows where to steer the train?

I've installed GPS in about a 100 locomotives. They are so cheap now, that they will all have it soon enough

Only one reason why it (GPS) is there. To run the train without crewmen aboard to look out the window to know where they know exactly where they're at, is the only reason it is there.

If you're reading this in 2022, that worked out real well, didn't it?

Oh well. No one is going to miss San Bernardino anyway...

You mean so the Engineer knows where to steer the train?

The driver doesn't have to remember a thing. His route is controlled by signals. He just has to follow speed limits and stop safely at stations.

There is an event recorder (like an airplane's "black box") in the cab of most railroad locomotives. Despite the fact that many modern locomotives are highly automated, there is no short cut when it comes to knowledge of the operating rules. That requires a good memory, the ability to interpret and apply training to every situation--it is a combination of knowledge, memory, skill and experience that keeps everyone safe on the rails.