Issue : Inconsistent `model.train()` calls in the training loop.

The code calls `model.train()` twice within the inner training loop (once before the loop and once inside). The second call is redundant and unnecessary.

```python
model.train()
for batch_idx, (features, targets) in enumerate(train_loader):
    model.train() # redundant call

    features = features.to(device)
    targets = targets.to(device)
```