There are some things I spend money on and some things I am cheap about. Fast clocks fall in to the cheap category. They just seemed very expensive and by design my layout would need three. I have been down 3 different roads so far over time.
1. I tried to used the Digitrax built in clock but I found that it didn't keep very good time and you need everyone to have a DT402x throttle to be able to see the time and then you have to train everyone to use it. I also tried this with JMRI but still didn't like how it worked. Sometimes if you wait things will look after themselves.
2. One day while looking for fast clocks on the net I found the Windows Fast Clock developed by Wesley Steiner. So I loaded/opened it on my laptop and my tablet and my phone. There, now I have 3 fast clocks, my laptop at the Melville yard, my tablet in staging and it sits on the deep freeze bedside the paper work and my phone which is in the other part of the main room. I have an adapter for my phone so it can be mounted on my tripod. The only problem with this system is that you have to start all 3 devices one at a time, this only leaves a few seconds between start times so it worked well. The other problem is that all my devices want to shut down. The laptop is easy to adjust and is set to not shut down because I use it during ops for other things anyway. One of the things that runs on it is JMRI and WiThrottle so operators can use their phones as throttles or one of the old phones I have acquired that can be used as throttles. The longest I could set my phone and tablet so it would not go to sleep was 30min which means you have to give them a tap on the screen every so often so their timers for sleep mode reset. Sounds easy but every once in a while they are forgotten and the clocks they are running will stop. It can be a bit of a pain.
If you only need one clock this system works very well and has lots of different choices, my needs are just a little more complicated. You can even have a analog clock face if you like.
3. I was once again surfing the net and came across an app called Model Railroad Fast Clock on Google Play. I don't know if it is available for Apple because I don't own any Apple devices. So I loaded it on my phone and it has some awesome features. The biggest ones are when it is running it will stop your device from going to sleep and it has Bluetooth so I can Bluetooth all 3 together. I only have to set the time once on one device. I have since acquired another tablet the same as my first one from a friend that changed over to an iPad ??? good for me. Now the second tablet replaces my laptop as the app is not yet available for windows. I have asked the developer if it is possible to have it work with windows. The other thing about the Bluetooth is that anyone who has the app can get this time on their phone, which is also a bonus if they are using it as a throttle. This is the one I am going with now and it seems to work great so far. Technology is amazing at times. FREE
So I run 4-1 fast clock most of the time. On the EMRA in Edmonton Peter runs their fast clock also at 4-1 but will adjust the speed up and down depending on how things are going. He will run slower at the start of a session so the yard ops can get up to speed , as they may be new to the position or have not run the yards for a while. Then when things start coming together he speeds it up. The other thing about this is if you have time gaps in your timetable so as no to overload the layout I can speed things up to 6-1 for a while to keep things moving. That way ops don't get bored. And by changing these times you can remove stress from the ops that are still learning to give them a better experience.
There are links on my links page for these fast clocks.