My recommendation is we start here:
Construct the route from start station to end station in a profile view first, before doing anything else. We shall add stations and name sections also as we go.

When it is completed in this phase, we can then move on to the next phase, placing curves where necessary, with other landmarks such as bridges and crossings.

Make sure that you do not set ANY TUNNELS at this stage, or else it may not be possible to reverse the direction of your route.

Starting out:
We shall first construct the line as double track, absolutely straight apart from rise and fall.

Name the route by selecting Alt-F8 and typing the start and end stations of the route in as requested, with a maximum of 79 characters (this is limited by the dimensions of a DOS screen). Hit Enter to complete the operation. You may always change it later by Alt-F8 and retyping it. If you hit Alt-F8 and then decide you don't wish to change it after all, just accept it with Enter.

All RailSim start stations are four tracks with two island platforms.

Name the starting station by pressing F8 and typing in the name of the station which cannot be longer than 20 characters. Enter, and type an abbreviated code of a maximum of 3 characters for timetable purposes. Enter again. This brings you back to the editor screen.

If you F8 and decide to keep what is there, press Enter and it will remain. If you wish to remove the section identification, press the spacebar one or more spaces, Enter and you are back in the editor.

If you wish the section identification to be the same as the preceding one, press Shift-F8 instead, while you are still in the editor.

Route Rise and Fall - its gradient:

The 50-year old gradient profile above tells us spot heights of specific locations, against a horizontal distance from the starting point. It tells us the minimum height above mean sea level, the ruling gradient in each section, and minimum curvature radius. More recent profiles will usually give a track curvature schematic on there as well, where the actual length of what radius curves can easily be calculated.

How to do it:
Using the triangular arrow keys < and > located just the the right of - and one row above - the space-bar, you set up and down positioning of the track.

Increasing Gradient: - >
This makes the track climb, or climb more steeply than it did before.

The gradient is shown, not as percentage (1/100), but per in units per 1000, so that a grade of 2% is shown as 20 o/oo. Consequently a gradient of 2.6% is shown as 26%o.

Gradient increases or decreases in increments of 0.2%, and the current gradient is shown in the status line at the bottom of the editor screen, along with other information including the Mile Post, the Track Speed Limit, and what lineside feature corresponds to that position In this case an Automatic signal, called a Permissive signal in SAR/AN terminology as can be seen in the screen capture below.

Decreasing Gradient: - <
This makes the track descend, or descend more steeply than it did before.

This is purely the reverse operation from the pervious one.

You may find that you need to vary the gradient in the editor to be steeper or less steep than the real gradient; this is because of the way the editor works. However the resulting track file is a very good approximation to the real thing.

Route Profile - F9
The program will produce a gradient profile for your line, visible at any time by pressing the F9 key while in the editor. In here you can check your progress, varying the climb and descent to get the spot height at the intermediate stations right. The Gradient profile is also displayed for your confirmation at the beginning of the simulation, after having selected the route from the opening menu.

If you have a long line with many intermediate stations and little rise and fall, it is perhaps wise to get each gradient correct before moving on to the next, because otherwise in the profile diagram the text from one site may well cover the next as you can see on the right hand side of that profile diagram.

Having reached where a station should be placed, it is good practice to create a level area so that trains do not have to wait on a slope for another to cross or pass with their brakes on. It takes time to release the brakes, and puts additional strain on them. In real life, it would be difficult to shunt cars, and park them in sidings as well.

Stations
Insert a "stop", "siding" or "station" at each location where a station is situated, or else the actual height will not be displayed on the profile diagram the editor draws. My preference is for a "stop" as it is quick and easy to remove later. Use the Right and Left Cursor Keys to scroll through the choices of what to place on the track. Use Insert to place the item, or Delete to remove it.

It will arbitrarily assign a name for its location, which you can change using F8. In the case of the illustration above, it ihas been renamed Murray Bridge, representing the town on the River Murray from which the line climbs heading westwards towards the Mount Lofty summit, before dropping down again to Adelaide.

A loop for crossing or passing can also be named, by creating a Siding which has no platform as can be seen here. Stations and Sidings are symmetrical in RailSim, with exactly 1 mile between opposite end points (switches), and in the case of a station, the platform centre is midway.

If the station building is on the wrong side of the line, press E and it will jump to the other side. This is true of stations, start and end stations, and stops, but not sidings (which have no building).

If you need to place the platform near to the switches at one end, you have to construct double track trackwork, and place a Stop where you want the platform to be. A Stop may be placed on single or double track lines, but not on a siding.

In the case below, it is located adjacent to a road crossing and also has a "Home" signal immediately after it, protecting a facing switch into double tracks, providing a short loop through the following station for passenger railcars to pass one another.

Repeat this procedure for each station, checking rise and fall against the actual height shown on the electronic profile against your information from the railway company.

Station Placement Restrictions
There has to be 1.5 miles clear between stations and sidings, including start and end stations.

Stops, however, may be placed within half a mile of stations and sidings, and other stops.

End Station
When you reach your destination, make sure the gradient is zero before inserting the end station. Remember that until you actually place an End Station you are unable to save the route.

This end station - like all RailSim end stations - has four island platforms arranged as shown.

Having got there, save the file you have just created by pressing Esc. You will be greeted by a Warning screen like this one, because your railway has not had any signals placed on it yet...

So, do as it says, any key press will acknowledge it.

Now, it will prompt you QUIT EDITOR [Y/N]? If you select N for No, you will continue in the editor at the position you are presently.

If you select Y for Yes, you can save and continue, but you will be back at the starting point of the line when you return to the editor.

Select Y (for yes, and it will prompt you with a directory which may have a few routes in it.

You may use another directory (you have a choice of 10) by using the enter key to scroll through the available directories. Type the letter for the position in the menu you wish to fill - there is a choice of 26. It will save it against the name you entered earlier.

geography - gradients - curves - features - speeds - reversing the route