This experience should help you understand why it is not a good idea to use Global variables. However, if you wish to continue doing so it would make sense to put your global variables in a Class with the Predeclared ID set to true.
For example, if you create a Class called Glb which contains your Global variables (and only these variables) you get the following advantages
You know where the global variables are located.
You get easy intellisense for your global variables. e.g. typing 'Glb.' will bring up the list of your global variables which cuts down on typos and memory stress
If you need to do any checks on the values assigned to a Global variable this can be done in the Glb Class.
I'd recommend the use of the free and fantastic Rubberduck addin for VBA Amongst this addins many talents is the use of comments as annotations e.g. "'@PredeclaredId" which makes setting the Predeclared attribute of a Class mostly painless.
You can start your global class with just the variable declarations
'@PredeclaredId
'@Exposed
Option Explicit
Public LastColumnBck As Long
Public wsbck As Worksheet
Public datebck As String
Public linebck As String
Public TargetRowBck1 As Integer
Public TargetRowBck2 As Integer
Public StationRowBck As Integer
When you need to start adding validation code you can use Rubberduck's Field Encapsulation refactoring to transform you variables into properties
[![Field Encapsulation refactoring][1]][1]
which will give you the following code for 'free'
Option Explicit
Private Type TClass1
LastColumnBck As Long
Wsbck As Worksheet
Datebck As String
Linebck As String
TargetRowBck1 As Integer
TargetRowBck2 As Integer
StationRowBck As Integer
End Type
Private this As TClass1
Public Property Get LastColumnBck() As Long
LastColumnBck = this.LastColumnBck
End Property
Public Property Let LastColumnBck(ByVal RHS As Long)
this.LastColumnBck = RHS
End Property
Public Property Get Wsbck() As Worksheet
Set Wsbck = this.Wsbck
End Property
Public Property Set Wsbck(ByVal RHS As Worksheet)
Set this.Wsbck = RHS
End Property
Public Property Get Datebck() As String
Datebck = this.Datebck
End Property
Public Property Let Datebck(ByVal RHS As String)
this.Datebck = RHS
End Property
Public Property Get Linebck() As String
Linebck = this.Linebck
End Property
Public Property Let Linebck(ByVal RHS As String)
this.Linebck = RHS
End Property
Public Property Get TargetRowBck1() As Integer
TargetRowBck1 = this.TargetRowBck1
End Property
Public Property Let TargetRowBck1(ByVal RHS As Integer)
this.TargetRowBck1 = RHS
End Property
Public Property Get TargetRowBck2() As Integer
TargetRowBck2 = this.TargetRowBck2
End Property
Public Property Let TargetRowBck2(ByVal RHS As Integer)
this.TargetRowBck2 = RHS
End Property
Public Property Get StationRowBck() As Integer
StationRowBck = this.StationRowBck
End Property
Public Property Let StationRowBck(ByVal RHS As Integer)
this.StationRowBck = RHS
End Property
The use of the 'Predecalred' attribute means that you get a default instance of the class i.e. you don't have to New a Glb object. Of course by setting the predeclared attribute to true you are also committing to using just the Glb instance and not creating instances. Multiple instances of the global variables are guaranteed to give you a headache.
Be warned though, by using a Class in this manner you will be taking the first tentative steps to using Objects in VBA rather than a mishmash of functions in Modules.
[1]: https://i.sstatic.net/WcSMM.jpg