diff --git a/egs/wsj/s5/steps/libs/nnet3/xconfig/basic_layers.py b/egs/wsj/s5/steps/libs/nnet3/xconfig/basic_layers.py
index 7c01689e86c..aa301eb4398 100644
--- a/egs/wsj/s5/steps/libs/nnet3/xconfig/basic_layers.py
+++ b/egs/wsj/s5/steps/libs/nnet3/xconfig/basic_layers.py
@@ -998,7 +998,8 @@ def set_default_configs(self):
         self.config = {'input': '[-1]',
                        'dim': -1,
                        'cepstral-lifter': 22.0,
-                       'affine-transform-file': ''}
+                       'affine-transform-file': '',
+                       'write-init-config': True}
 
     def check_configs(self):
         if self.config['affine-transform-file'] is None:
@@ -1030,6 +1031,13 @@ def get_full_config(self):
         output_dim = self.output_dim()
         transform_file = self.config['affine-transform-file']
 
+        if self.config['write-init-config']:
+            # to init.config we write an output-node with the name 'output' and
+            # with a Descriptor equal to the descriptor that's the input to this
+            # layer.  This will be used to accumulate stats to learn the LDA transform.
+            line = 'output-node name=output input={0}'.format(descriptor_final_string)
+            ans.append(('init', line))
+
         idct_mat = common_lib.compute_idct_matrix(
             input_dim, output_dim, self.config['cepstral-lifter'])
         # append a zero column to the matrix, this is the bias of the fixed