Private Sub timeaftertime()
 
        Dim lines As New _
        System.Collections.Generic.SortedDictionary(Of Date, String)
 
        Using sr As New IO.StreamReader("C:\Daten\Times.txt")
            Dim line$, parts$()
            While Not sr.EndOfStream
                line = sr.ReadLine
                parts = line.Split(" "c)
                If parts.Length > 1 Then
                    'Alternative (result: Date) - aber nicht zur Geisterstunde!
                    'If Date.TryParse(parts(1), result) Then
                    '    lines.Add(result, line)
                    'End If
 
                    parts = parts(1).Split(":"c)
                    If parts.Length > 1 Then
                        lines.Add _
                        (New Date(1, 1, 1, CInt(parts(0)), CInt(parts(1)), 0), _
                        line)
                    End If
                End If
            End While
        End Using
 
        Using sw As New IO.StreamWriter("C:\Daten\times_sort.txt")
            For Each line As KeyValuePair(Of Date, String) In lines
                sw.WriteLine(line.Value)
            Next
        End Using
    End Sub

 Private Class SubstringComparer
        Implements System.Collections.Generic.IComparer(Of String)
 
        Dim _splitchar As Char
        Dim _blockindex As Integer
 
        Public Sub New(SplitChar As Char, Blockindex As Integer)
            _splitchar = SplitChar
            _blockindex = Blockindex
        End Sub
 
        Public Function Compare(x As String, y As String) As Integer _
            Implements System.Collections.Generic.IComparer(Of String).Compare
 
            Dim x1 As String = x.Split(_splitchar)(_blockindex)
            Dim y1 As String = y.Split(_splitchar)(_blockindex)
 
            Return x1.CompareTo(y1)
        End Function
    End Class

  Dim lines() As String = IO.File.ReadAllLines("C:\daten\times.txt")
 
  Array.Sort(lines, New SubstringComparer(" "c, 1))
 
  IO.File.WriteAllLines("C:\daten\times_sort.txt", lines)