In his comment, Michal has asked about the ability to execute IOS commands with prompts from Tcl shell. I haven't found a generic solution yet, but you can reload a router from a Tcl script. First you have to define an EEM applet that reloads the router and can be triggered from command-line interface:
event manager applet forceReloadNow you can use the exec "event manager run forceReload" Tcl command in your Tcl script to run the applet (and reload the router).
action 1.0 reload