Use nn.Sequential().add_module or OrderedDict.
# OrderedDict
self.conv5 = nn.Sequential(OrderedDict({
            'conv': nn.Conv2d(out_channels[2], out_channels[3], 1),
            'bn': nn.BatchNorm2d(out_channels[3]),
            'relu': nn.ReLU(inplace=True),
        }))

# add_module
self.conv5 = nn.Sequential()
self.conv5.add_module('conv', nn.Conv2d(out_channels[2], out_channels[3], 1))
self.conv5.add_module('bn', nn.BatchNorm2d(out_channels[3]))
self.conv5.add_module('relu', nn.ReLU(inplace=True))

Then you can use net.conv5.conv to track this conv.