diff --git a/package/MDAnalysis/lib/trans.pyx b/package/MDAnalysis/lib/trans.pyx
new file mode 100644
index 00000000000..8068c17a737
--- /dev/null
+++ b/package/MDAnalysis/lib/trans.pyx
@@ -0,0 +1,29 @@
+import numpy as np
+cimport cython
+cimport numpy as np
+
+
+@cython.boundscheck(False)
+@cython.wraparound(False)
+def residue_positions(
+        float[:, :] coords not None,
+        long[:] indices not None):
+    cdef Py_ssize_t i, j, k
+
+    cdef int n_items = indices.shape[0]
+    cdef int n_res = np.unique(indices).shape[0]
+
+    cdef long[:] counter = np.zeros(n_res, dtype=np.int64)
+    cdef float[:, :] output = np.zeros((n_res, 3), dtype=np.float32)
+
+    for i in range(n_items):
+        j = indices[i]
+        for k in range(3):
+            output[j, k] += coords[i, k]
+        counter[j] += 1
+
+    for i in range(n_res):
+        for k in range(3):
+            output[i, k] /= counter[i]
+
+    return np.asarray(output)
diff --git a/package/setup.py b/package/setup.py
index 605446d56e5..f6b05a0a58b 100755
--- a/package/setup.py
+++ b/package/setup.py
@@ -310,9 +310,12 @@ def extensions(config):
     util = MDAExtension('lib.formats.cython_util',
                         sources=['MDAnalysis/lib/formats/cython_util.pyx'],
                         include_dirs=include_dirs)
+    trans = MDAExtension('lib.trans',
+                         sources=['MDAnalysis/lib/trans.pyx'],
+                         include_dirs=include_dirs)
 
     extensions = [dcd, dcd_time, distances, distances_omp, qcprot,
-                  transformation, xdrlib, util]
+                  transformation, xdrlib, util, trans]
     if use_cython:
         extensions = cythonize(extensions)
     return extensions