The TP associated with the GSLR in Find Places actually takes you to the station in Slate, but I reccommend beginning your ride at the terminal station in Purple.
The ride ends abruptly in Mocha (the end of the line anyway) where some delightful individual has littered the track with plywood cubes.
The train dissappears after a bit so that it can re-rez in less hostile conditions.
The head of the "Great Second Life Railway Group" is Athos Murphy who's profile informs us:
"The locomotive (based on a Midland Railway 4-2-2 steam engine built in 1900) and the carriage (based on an 1890s private coach in Britain) are currently just test items, to work on scripts and to determine clearances and visual effect. The Slate station is based on Wingfield station, also in Britain; the signal and viaducts are also based on British practice. Scripts for waypoint-based motion, the interior experience, scheduling, and audio files are underway."
I am looking forward to these additions, trains are a great way to see the world.
The SLRR is tracked by a talking map in ANWR:
As you can see, the SLRR is still in development. The map only has indicator lights from Tuliptree to Jubata although track has been laid all the way to Bhaga. I teleported to the Tuliptree Station (conveniently located at almost the dead center of the sim) and waited and waited and waited for a train.
There is a nice little picnic area provided by Abelard Ash just behind the station.
When no train appeared, I flew along the tracks (through many sims) to Jubata without finding it. Perplexed, I returned to ANWR to see if the map could give any more information. The indicator light was blinking red, north of Achemon, and the map was no longer talking. I decided to check the section of track on foot, but still didn't find the train. I can only guess that a Physics Accident or a Return to Inventory occurred, and the last place the train was seen was the location of the blinking red light.
According to the map, the train should be right around the bend...
When the train is up and running, I am certain that a ride on the SLRR is entertaining. Each station has its own unique look, and I noticed many other areas of interest (Including the Hobo Railroad in Calcutta which could be a Baedeker entry all by itself!) as I flew along the tracks. The locations of future stations are marked with "temporary platforms" of concrete. The SLRR is an ambitious Linden project, and one that I hope will not fall by the wayside (although I hope the inventory copy bug has a higher priority).
The Purple Terminal, Purple (136, 203, 25)
The Plywood Cube End of the Line, Mocha (227 208 42)
The SLRR Map, ANWR (96, 165, 35)
SLRR Tuliptree Station, Tuliptree (128, 128, 0)
Bhaga Terminal, Bahga (95, 38, 28)
Calleta's Hobo Railroad Infohub, Caletta (129, 207, 27)