diff --git a/pytorch_lightning/models/trainer.py b/pytorch_lightning/models/trainer.py
index 5ce253c29c..e60a0d95cc 100644
--- a/pytorch_lightning/models/trainer.py
+++ b/pytorch_lightning/models/trainer.py
@@ -772,7 +772,7 @@ class Trainer(TrainerIO):
             output = self.model.training_step(data_batch, batch_nb)
 
         try:
-            model_specific_tqdm_metrics_dic = output['tqdm_metrics']
+            model_specific_tqdm_metrics_dic = output['prog']
         except Exception as e:
             model_specific_tqdm_metrics_dic = {}
 
diff --git a/pytorch_lightning/testing_models/lm_test_module.py b/pytorch_lightning/testing_models/lm_test_module.py
index 87de2c7777..8e0718b972 100644
--- a/pytorch_lightning/testing_models/lm_test_module.py
+++ b/pytorch_lightning/testing_models/lm_test_module.py
@@ -96,12 +96,15 @@ class LightningTestModel(LightningModule):
         if self.trainer.use_dp:
             loss_val = loss_val.unsqueeze(0)
 
-        output = OrderedDict({
-            'loss': loss_val
-        })
-
-        # can also return just a scalar instead of a dict (return loss_val)
-        return output
+        # alternate possible outputs to test
+        if self.trainer.batch_nb % 1 == 0:
+            output = OrderedDict({
+                'loss': loss_val,
+                'prog': {'some_val': loss_val * loss_val}
+            })
+            return output
+        if self.trainer.batch_nb % 2 == 0:
+            return loss_val
 
     def validation_step(self, data_batch, batch_i):
         """