The HotBar does not support drag and drop (never has). Reasons are complex and besides the point right now.

How to use it - 
- Select an object in the bar.  (Left-Click and release) <the selected item is boxed in Grey>
-Move cursor to the Layout (you can drag here but it doesn’t do anything which is why you are confused).
- Left-Click again on the surface <the cloned object appears in red>
- You can now left-click and drag to reposition the object.
- Right-click and drag rotates the object
- Shift and left-click for a turnout selects a different endpoint to snap into other track
- To accept the object hit Space <object drawn normally>

- Another left click on the layout adds another clone.
- Esc rejects the selected object and resets the command so no objects are selected.

incidentally you can also add using the Add->Turnout window, which you might find more natural and gives you a visual of which endpoint is selected.

in Train mode,  the “click to select”, “move cursor”, “click and drag to place” works the same way for Cars.

Hope that helps.

Adam