diff --git a/boxmox/data.py b/boxmox/data.py
index 45c744f38890af382e7f0583ddf84a109ada88a6..0c90e795fd1363221f3317a4ae9e564659033e4d 100644
--- a/boxmox/data.py
+++ b/boxmox/data.py
@@ -83,15 +83,15 @@ class InputFile17:
         '''
         return len( [ x for x in self.anc.keys() ] )
     def __getitem__(self, item):
-        return [ self.__data[i] for i in item ] if isinstance(item, list) else self.__data[item]
+        return [ self._data[i] for i in item ] if isinstance(item, list) else self._data[item]
     def __setitem__(self, item, values):
         if isinstance(item, list):
             for i, v in zip(item, values):
-                self.__data[i] = v
+                self._data[i] = v
         else:
-            self.__data[item] = values
+            self._data[item] = values
     def keys(self):
-        return self.__data.keys()
+        return self._data.keys()
 
     def read(self, fpath):
         '''
@@ -109,7 +109,7 @@ class InputFile17:
             self.time     = [ x[0] for x in dmp ]
             ntime = 1
         self.anc        = { hdr[i]: [ x[i] for x in dmp ] for i in range(ntime, ntime+nanc) }
-        self.__data     = { hdr[i]: [ x[i] for x in dmp ] for i in range(ntime+nanc, len(dmp[0])) }
+        self._data     = { hdr[i]: [ x[i] for x in dmp ] for i in range(ntime+nanc, len(dmp[0])) }
 
     def __str__(self):
         f = StringIO.StringIO()
@@ -137,10 +137,10 @@ class InputFile17:
 
         if isinstance(self.time, list):
             for itime, xtime in enumerate(self.time):
-                line = [ xtime ] + [ self.anc[key][itime] for key in anc_names ] + [ self.__data[key][itime] for key in data_names ]
+                line = [ xtime ] + [ self.anc[key][itime] for key in anc_names ] + [ self._data[key][itime] for key in data_names ]
                 f.write(' '.join('{0:e}'.format(x) for x in line) + '\n')
         else:
-            data_line = ' '.join( '{0:e}'.format(float(self.anc[x])) for x in self.anc.keys() ) + ' ' + ' '.join( '{0:e}'.format(float(self.__data[x])) for x in self.keys() ) + '\n'
+            data_line = ' '.join( '{0:e}'.format(float(self.anc[x])) for x in self.anc.keys() ) + ' ' + ' '.join( '{0:e}'.format(float(self._data[x])) for x in self.keys() ) + '\n'
             if not self.time is None:
                 data_line = '{0:e}'.format(float(self.time)) + ' ' + data_line
             f.write(data_line)
@@ -153,7 +153,7 @@ class InputFile17:
 
         self.anc        = {}
 
-        self.__data     = {}
+        self._data     = {}
 
         self.version    = version
 
@@ -179,17 +179,17 @@ class InputFileOrig:
         '''
         Number of variables.
         '''
-        return len( [ x for x in self.keys() if not x is self.__timeVar ] )
+        return len( [ x for x in self.keys() if not x is self._timeVar ] )
     def __getitem__(self, item):
-        return [ self.__data[i] for i in item ] if isinstance(item, list) else self.__data[item]
+        return [ self._data[i] for i in item ] if isinstance(item, list) else self._data[item]
     def __setitem__(self, item, values):
         if isinstance(item, list):
             for i, v in zip(item, values):
-                self.__data[i] = v
+                self._data[i] = v
         else:
-            self.__data[item] = values
+            self._data[item] = values
     def keys(self):
-        return self.__data.keys()
+        return self._data.keys()
 
     def read(self, fpath):
         '''
@@ -201,8 +201,8 @@ class InputFileOrig:
             dmp               = _mygenfromtxt(f)
 
         if not self.timeFormat == 0:
-            self.__timeVar  = dmp.dtype.names[0]
-        self.__data     = { x: dmp[x] for x in dmp.dtype.names }
+            self._timeVar  = dmp.dtype.names[0]
+        self._data     = { x: dmp[x] for x in dmp.dtype.names }
 
     def __str__(self):
         f = StringIO.StringIO()
@@ -218,22 +218,22 @@ class InputFileOrig:
             f.write('{0:1d}'.format(0)                  +'\n')
         f.write('{0:1d}'.format(self.timeFormat)            +'\n')
 
-        column_names = [ key for key in self.keys() if key != self.__timeVar ]
-        if self.__timeVar in self.keys() and str(self.timeFormat) != "0" :
-            f.write('{0:s}' .format(' '.join([self.__timeVar] + column_names)) + '\n')
+        column_names = [ key for key in self.keys() if key != self._timeVar ]
+        if self._timeVar in self.keys() and str(self.timeFormat) != "0" :
+            f.write('{0:s}' .format(' '.join([self._timeVar] + column_names)) + '\n')
 
-            for itime, xtime in enumerate(self.__data[self.__timeVar]):
-                line = [ xtime ] + [ self.__data[key][itime] for key in column_names ]
+            for itime, xtime in enumerate(self._data[self._timeVar]):
+                line = [ xtime ] + [ self._data[key][itime] for key in column_names ]
                 f.write(' '.join('{0:e}'.format(x) for x in line) + '\n')
         else:
             f.write('{0:s}' .format(' '.join( column_names)) +'\n')
-            f.write(' '.join( '{0:e}'.format(float(self.__data[x])) for x in self.keys() ) + '\n')
+            f.write(' '.join( '{0:e}'.format(float(self._data[x])) for x in self.keys() ) + '\n')
 
     def __init__(self, fpath=None):
         #: Time format (0: constant, 1: seconds since start, 2: hour of diurnal cycle)
         self.timeFormat  = 0
-        self.__timeVar   = 'time'
-        self.__data      = {}
+        self._timeVar   = 'time'
+        self._data      = {}
 
         self.version     = 0.0