diff --git a/reduce_sinex_size.py b/reduce_sinex_size.py
new file mode 100644
index 0000000..4877733
--- /dev/null
+++ b/reduce_sinex_size.py
@@ -0,0 +1,47 @@
+#!/usr/bin/env python3
+
+# This script reduces the size of the SINEX file by removing the
+# velocity parameters (which are not needed for this workflow).
+# If velocity parameters are needed, then change the function call
+# to remove_matrixzeros_sinex() insetad of remove_velocity_sinex() below.
+# This will remove zero lines only from +SOLUTION/MATRIX_ESTIMATE block,
+# Whilst reatining the velocity parameters.
+#
+# NOTE: this file does overwrite the input file, but a copy is made,
+#       with the extension tag "VEL"
+#
+#
+# Usage: reduce_sinex_size.py
+
+import os
+import glob
+import geodepy.gnss
+import sys
+from shutil import copy2
+
+# Get the path to the home directory and move to the working directory
+home = os.path.expanduser("~")
+os.chdir(home + '/apref/workDir/')
+
+# Get the input file name
+files = glob.glob('apref*.snx')
+
+if not files:
+    sys.exit('There is no APREF SINEX file by that name in the working directory')
+
+if len(files)> 1:
+    sys.exit('There are multiple APREF SINEX files in the working directory') 
+
+ifile = files[0]  
+
+# Make copy of original file
+copy2(ifile, f"{ifile}.VEL")
+
+# Remove velocity parameters and rename output file
+try:
+    geodepy.gnss.remove_velocity_sinex(ifile)
+except: 
+    raise NameError("Velocities could not be removed from sinex file")
+
+ofile = ifile
+os.rename('output.snx', ofile)