dynamic_cast<GLtk::Button *>(get_item(widgets, "btn_off"))->signal_clicked.connect(sigc::mem_fun(this, &MainWindow::off_clicked));
dynamic_cast<GLtk::Button *>(get_item(widgets, "btn_halt"))->signal_clicked.connect(sigc::mem_fun(this, &MainWindow::halt_clicked));
dynamic_cast<GLtk::Button *>(get_item(widgets, "btn_trains"))->signal_clicked.connect(sigc::mem_fun(this, &MainWindow::trains_clicked));
dynamic_cast<GLtk::Button *>(get_item(widgets, "btn_off"))->signal_clicked.connect(sigc::mem_fun(this, &MainWindow::off_clicked));
dynamic_cast<GLtk::Button *>(get_item(widgets, "btn_halt"))->signal_clicked.connect(sigc::mem_fun(this, &MainWindow::halt_clicked));
dynamic_cast<GLtk::Button *>(get_item(widgets, "btn_trains"))->signal_clicked.connect(sigc::mem_fun(this, &MainWindow::trains_clicked));